rdso training report -navin dixit

RDSO Summer Training 2014

1

S.no. Page no

1. Acknowledgement 02

2. Introduction 03

3. Testing Directorate 06

4. Test cell laboratory 07

(a Quality of ride 08

(b Stability & Dynamic forces 10

(c Drailment coefficient 13

(d Instrumentation 14

5. Fatigue testing laboratory 17

(a 100 ton system 17

(b 500 ton system 19

(c Stress measurements 24

6. Brake dynamometer laboratory 27

(a Test procedure and particulars 29

7. Air brake laboratory 32

(a Types of AB system 34

(b Working principle 35

(c Salient features 38

(d AB system test rig 41


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Creation of this report is influenced by numerous persons working

under the esteemed organization established by Indian Government

, RDSO. It is an archetype of best research center of India. As

engineers the training experience have explored an another

dimension and platform for our thinking .

I would like to express our sincere gratitude to Mr. D. K. Srivastav

(Testing Directorate Head of RDSO) for providing administrative

permission for my summer training and Also igniting curiosity and

emancipating our thinking from the boundary of engineering .

I am thankful to all the lab in-charge and superintendents and

with whose support and guidance the creation of report came to

existence .

I duly express my indebtness to Mr. Rajesh Gupta (Incharge

Training) for their kind support in helping me get settled in an

entirely new space to work and gain.

I am very thankful to Mr. H.N. Gupta(visiting faculty) for

enhancing my technical knowledge which made the understanding

of practical concepts easy.

Last , but not the least our gratitude and indebtness are also due to

some unnamed persons who remained unexpressed in words.

-Navin Dixit

B.tech (ME)


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Indian railways is a mammoth organization with a budget

running in to the thousands of crores and with a employee rtrength

of 1.6 million much more than the strength of Indian army.Such a

big organization like the IR can not run efficiently without

adequate R&D and design support. This is provided by RDSO at

lucknow.

Railways were introduced in India in 1853 and as their

development progressed through to the twentieth century, several

companies managed and state-owned railway systems grew up. To

enforce standardization and co-ordination amongst various

railway systems, the Indian Railway Conference Association (IRCA)

was set up in 1903, followed by the Central Standards Office (CSO) in

1930, for preparation of designs, standards and specifications.

However, till independence, most of the designs and manufacture of

railway equipments was entrusted to foreign consultants. With

Independence and the resultant phenomenal increase in country‟s

industrial and economic activity, which increased the demand of

rail transportation- a new organization called Railway Testing

and Research Centre (RTRC) was setup in 1952 at Lucknow, for

testing and conducting applied research for development of railway

rolling stock, permanent way etc.

Central Standards office (CSO) and the Railway Testing and

Research Centre (RTRC) were integrated into a single unit named

Research Designs and Standards Organization (RDSO) in 1957,

under Ministry of Railways at Lucknow.

The status of RDSO has been changed from an „Attached Office‟ to

„Zonal Railway‟ since 01.01.2003.


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ORGANISATION

RDSO is headed by a Director General. The Director General is

assisted by additional Director General, Sr. Executive Directors and

Executive Directors, heading different directorates. RDSO has

various directorates for smooth functioning:

Bridges and Structures , Carriage , Defense Research , Electrical

Loco , EMU & Power supply , Engine Development , Finance &

Accounts ,Geo-technical Engineering ,Quality Assurance,

Metallurgical & Chemical,Motive Power, Psycho-technical , Research

,Signal , Telecommunication ,Track ,Testing,Track Machines &

monitoring, Traction Installation, Traffic, Wagon

All the directorates of RDSO except Defense Research are located at

Lucknow. Cells for Railway Production Units and industries, which

look after liaison, inspection and development work, are located at

Bangalore, Bharatpur, Bhopal, Mumbai, Burnpur, Kolkata,

Chittaranjan, Kapurthala, Jhansi, Chennai, Sahibabad, Bhilai and

New Delhi.

QUALITY POLICY

To develop safe, modern and cost effective Railway technology

complying with Statutory and Regulatory requirements, through

excellence in Research, Designs and Standards and Continual

improvements in Quality Management System to cater to growing

demand of passenger and freight traffic on the railways.

FUNCTIONS

RDSO is the sole R&D organization of Indian Railways and

functions as the Technical advisor to Railway Board, Zonal

Railways and Production Units and performs the following

important functions:

Development of new and improved designs.


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Development, adoption, absorption of new technology for use

on Indian Railways.

Development of standards for materials and products specially

needed by Indian Railways.

Technical investigation, statutory clearances, testing and

providing consultancy services.

Inspection of critical and safety items of rolling stock,

locomotives, signaling & telecommunication equipment and

track components.

RDSO‟s multifarious activities have also attracted attention of

railway and non-railway organizations in India and abroad.


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Testing Directorate is the premier directorate of RDSO undertaking

design validations of all newly designed/modified rolling stock

developed in-house or imported, employing the latest state-of-the-

art data acquisition and analysis tools and techniques. Besides

undertaking actual field trials, this directorate has three

laboratories for conducting stationary tests as well.

In the year 1989 the present Testing directorate was created for

carrying out all dynamic and static mechanical testing activities of

all type Railway Rolling stocks. This directorate is looked after by

Executive Director Research Testing.

The various tests and trials done by Testing Directorate can be

broadly classified into Field Trials and Laboratory Tests. Field Trials

are those trials which are conducted on newly designed prototypes

and modified rolling stock, for assessing ride quality and ride

comfort apart from Route proving runs, Brake trials and Coupler

force trials to assess their behavior in actual operating conditions.

Testing Directorate has also been entrusted with carrying out

periodic track monitoring runs on Rajdhani and Shatabdi routes.

Laboratory Tests are conducted on newly designed sub-assemblies

and Rolling Stocks components as well as quality audit check for

assessing the suitability by simulating service condition /field

condition in three well equipped and modernized laboratories.

Well-qualified, fully trained and vastly experienced dedicated team

of 11 officers and 52 mechanical and instrumentation supervisors of

the Directorate are geared to meet the challenges posed in the field

of testing of railway vehicles and their components.


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FIELD TRIALS OF ROLLING STOCK

Whenever a railway vehicle undergoes a modification or a new

vehicle design is sought to be introduced, Field Trials are

mandatory before the Commissioner of Railway Safety permits their

introduction into the Railway system.

Testing Directorate has five field units to conduct various Field

trials like Oscillation trials, Confirmatory oscillograph car runs,

Track Monitoring runs, Brake trials of passenger & goods trains,

Jerk trials, Emergency Brake trials, Coupler force measurement and

Rating & Performance trials of locomotives.

It includes following trials:

• Oscillation trial

• Emergency Braking Distance trials

• Coupler Force and controllability

• Rating and Performance of locomotives

• Stress investigation of prototype shell of coach/wagon

• Regular track monitoring run

• Confirmatory oscillograph car run of loco/coach

Oscillation trial is conducted on a new or modified design of

rolling stock, which is proposed to be cleared for running on IR

track. The purpose of oscillation trial is, thus, an acceptance of a

railway vehicle by conducting dynamic behaviour tests in

connection with safety, track fatigue and quality of ride.


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An oscillation trial can be commenced only after receipt of CRS

sanction. CRS sanction is accompanied by Joint Safety Certificate

from the Railway and Speed Certificate issued by RDSO. In addition,

documents like, „List of curves and bridges‟, „Permanent and

temporary speed restrictions‟ on the route from the railway

applicable on the day of run, „Test scheme‟ from the

sponsoring/design directorate and latest summarised „TRC results‟

for selected detailed test stretches are needed to conduct the trials.

The „test scheme‟ includes objective of trial, background of trial,

various trial conditions, measurements and parameters to be

recorded, design particulars of the test vehicle, load vs. deflection

charts for individual and nested springs, necessary drawings of

bogie, axle box etc for load-cell fitment, instrumentation etc.

The oscillation trial is carried out either on „Main line‟ for

operation at less than 110 kmph on 52 kg rail or on 90R rail track

and/or on „High-speed line‟ for operation at 110 kmph or above and

up to 140 kmph on track maintained to C&M1-Vol.1 standard.

Quality of Ride

Human sensation of comfort is dependent on displacement,

acceleration and the rate of change of acceleration. In other words,

the product of displacement, acceleration and the rate of change of

acceleration could be used as a measure of discomfort during

travel.

For sinusoidal vibration with β as the amplitude and as its

periodicity, the formula, developed by Dr. Sperling, hence known as

Sperling‟s Ride Index, can be derived as under:

Displacement: s = * sin t

Velocity: v = ds/dt = * cost

Acceleration: adv/dt = * * sin t

Impulse: I = da/dt = - * * cos t


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Thus, level of discomfort a * I * s

Taking the maximum value of parameters over the half wave of

displacement,

The level of discomfort (- )* (- )* (

or, 3

Defining the RI as a measure of discomfort,

RI 3

or, RI = k* 3 *

If „b‟ is the amplitude of acceleration, then, b = * and also, = 2f

where, f is the frequency of vibration. Substituting and in

equation (1) above,

RI = k * (-b/2)3 * 5

= - k * b3 /

= K * b3 / f

For an individual, the sensation of vibration varies according to an

exponential law and thus,

RI = 0.896 * (b3 / f )0.1 --------- (2) (for ride quality)

In order to take human reactions, the formula is modified taking

into a correction factor and thus,

RI = 0.896 * [b3 * (f) /f ]0.1 -------- (3) (for ride comfort)

The term Ride quality means that the vehicle itself is to be judged.

Ride comfort means that the vehicle is to be assessed according to

the effect of mechanical vibrations on people in the vehicle.

RIDE QUALITY

Ride Index Appreciation

1 very good


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2 good

3 satisfactory

4 accepted for running

4.5 not accepted for running

5 dangerous

RIDE COMFORT

Ride Index Appreciation

1 just noticeable

2 clearly noticeable

2.5 more pronounced but not unpleasant

3 strong, irregular but still tolerable

3.25 very irregular

3.5 extremely irregular, unpleasant, annoying, prolonged

exposure intolerable

4 extremely unpleasant, prolonged exposure harmful

Stability & Dynamic Forces

Vertical and lateral forces are developed between the rail and the

wheel as a result of dynamic interplay of track and vehicle

characteristics. It is important to understand these forces because of

their role in vehicle stability and track stresses. Generally these

forces can be classified into three categories, namely, static forces,

quasi-static forces and dynamic forces.


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Static forces arise due to static wheel load applied on the rail.

Quasi-static forces are developed due to one or several factors, which

are independent of the parasitic oscillations of the vehicle and do

not vary in a periodical manner. Centrifugal forces caused by cant

excess or deficiency, curving action on points and crossings and

forces due to cross winds fall in this category.

Dynamic forces are caused by track geometry and stiffness

irregularities, discontinuities like rail joints and crossings, wheel set

hunting and vehicle defects like wheel flats. Dynamic forces are the

most significant ones in the study of vehicle stability and rail

stresses and are also the most difficult to mathematically determine

or to experimentally measure.

According to Esveld, the frequency ranges for the vertical dynamic

forces are 0-20 Hz for sprung mass, 20-125 Hz for un-sprung mass

and 0-2000 Hz for corrugations, welds and wheel flats. The vertical

forces in the lower frequency range are produced due to vehicle

response to changes in the vertical track geometry like unevenness

and twist whereas forces in the higher frequency range are caused

by discontinuities like rail joints, crossings, rail and wheel surface

irregularities. A wheel flat produces high frequency peaks at regular

intervals, which is easily distinguishable from other surface

irregularities.

QSL

2B QSR

H C

YL

A B YR

QL

2G QR


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The net lateral forces acting on the track by the wheel set can lead

to the distortion of track laterally, causing derailment. In other

words, this force is a measure of lateral strength of the track. This

force is equal to the lateral force at axle box level as a result of

reaction of the wheel set with the vehicle body/bogie. This force,

usually denoted by the symbol Hy

, can be measured with the help of a

load-cell placed between the journal face and the axle box cover or

the bogie frame and the axle box.

In the given diagram, QR

or QL

is vertical wheel load at rail level, QSR

or QSL

is vertical wheel load measured at axle box level, 2B is

distance between springs, 2G is track gauge, C is axle height from

rail level and H is net compressive force measured at axle box level.

Taking moment of forces about point A or B, we get,

QR

= [(B+G)/2G]*QSR

– [(B-G)/2G]*QSL

+ [C/2G]*H

QL

= [(B+G)/2G]*QSL

– [(B-G)/2G]*QSR

- [C/2G]*H

Thus, measuring H and spring deflection can compute Q at rail

level computed by above formula.

„Off-loading‟ and „On-loading‟ of the test vehicle is represented in

percentage. It is calculated as % off-loading = 2*k*(-/P and % on-

loading = 2*k*(+ /P, where, is the spring deflection in mm, P is axle

load in tonnes and k is spring stiffness in tonnes/mm for springs

fitted on the wheel. To calculate maximum off-loading and on-

loading max is used, where, -max is maximum spring deflection in

expansion and +max is maximum spring deflection in compression.

The concerned Design Directorate furnishes the primary and

secondary spring heights at different axle loads, in a tabular form,

at increments of 0.5 tonnes along with the test scheme. The above

treatment assumes that the vertical forces due to the unsprung

masses remain at their static value. When a measuring wheel is

used, the maximum and minimum values of QL

and QR

are

determined. These values, when divided by the static wheel load,

indicate the true On-loading and Off-loading of the wheels.


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Derailment Coefficient

Derailment can happen when the values of lateral and vertical

forces acting at the rail-wheel contact point assume a critical

combination leading to mounting of the flange on the rail. This

phenomenon is known as derailment by flange mounting

All the theories that have been evolved to explain the phenomena of

derailment have tried to establish a suitable ratio between the

instantaneous values of lateral force and vertical force at the rail-

wheel contact point beyond which derailment may occur.

Mr J.Nadal, Chief Mechanical Engineer of French State Railway

propounded the earliest of these theories of derailment by wheel

flange mounting the rail in 1908.

Consider a flanged wheel supporting a load Q and subjected to a

lateral thrust Y passing round a curve. It is seen that the point of

contact between the flange and the rail will be slightly ahead of the

wheel center line so that at the point of contact the flange will have

a small movement downwards, producing a frictional reaction Y in

an almost vertical direction.

Q wheel

µY

wheel

Rail Y Rail

QR

µQR

The flange will begin to climb the rail as soon as the frictional force

µY exceeds the load Q. Let the flange make contact with the rail at


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some angle and the lateral force Y produce a reaction QR

from the

rail at the point of contact.

Then, resolving the forces, it is seen that if the wheel is not to derail,

Q Sin – Y Cos – QR > 0 --------------- (1)

QR = Y Sin + Q Cos --------------- (2)

Substituting QR

in equation (1),

Q Sin - Y Cos - [ Y Sin + Q Cos ] > 0

Or, Q [ Sin - Cos ] – Y [ Cos + Sin ] > 0

Or, Q [ Sin - Cos ] > Y [ Cos + Sin ]

Or, Y/Q < [ Sin - Cos ] / [ Cos + Sin ]

Or, Y/Q < [ tan - ] / [ 1 + tan ]

Where, Y and Q are the instantaneous values of the lateral and

vertical forces at the rail-wheel contact pointis the angle of

flange with horizontal plane and is the coefficient of static

friction between wheel tread and rail. It can be seen from Nadal‟s

formula that for =0.27 and =600

, Y/Q =0.997 or 1. This is the

limiting value beyond which the wheel flange will tend to mount on

the rail table. The other question is that of the duration for which

this ratio can exceed the value of 1. It is well known that derailment

by flange mounting is not an instantaneous, but a gradual process.

In Japanese Railways, the limiting value of Y/Q is taken as 0.04/t if t

is less than 1/20 seconds and 0.8 if exceeds 1/20 seconds.

Instrumentation

The instrumentation is done as per test scheme. Normally,

instrumentation used for recording data is transducers as input

device, signal conditioners as processing device and chart recorders

and/or computerised data acquisition system as output device.


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Power supply unit is used to provide power supply to signal

conditioners and recorders and excitation to passive transducers.

Transducers are used to measure acceleration, deflection and force.

Signal picked up from transducer is fed into signal conditioner for

processing. The processed output from signal conditioner can be

recorded on chart recorder and/or acquired on computer (PC or

laptop) through data acquisition cards.

Transducers normally used are passive types either resistive or

inductive. Transducer used for measurement of acceleration in x, y

and z directions is also called accelerometer and can be either

„strain gauge type‟ or „piezo electric‟. Transducer used for

measurement of deflection of spring, bolster, bogie movement etc

can be either LVDT, i.e., linear voltage differential transformer or

string-pot. Transducer used for measurement of force or load at axle

box level is normally a load-cell. Measuring wheel measures lateral

and vertical forces at rail wheel level. Transducers are excited either

by 5V rms 2.5 kHz AC or DC voltage to provide output signal.

Load cell assembly is used for recording lateral forces at axle box

level. Load cell of strut type is manufactured in-house suiting to the

axle box arrangement with range of measurement from 0 to 10t

compressive load only. Load cell is of full bridge resistance type and

calibrated with excitation voltage from 5 to 10V AC and under pre-

calibrated hydraulic jack. Its output is about 90 mV/V/tonnes. A

load cell calibration chart is prepared with load in tonnes on x-axis

and mV output on y-axis. The excitation voltage used during

calibration is mentioned in the chart. Care should be taken to use

the same excitation voltage during trial.

Measuring wheel is used for measuring vertical and lateral forces at

rail wheel level. FEM analysis of wheel conforming to s-shape web

profile is carried out to determine the strain gage locations sensitive

to vertical and lateral force. The strain gage locations used for

measurement of lateral force are having minimal effect of vertical

wheel load and similarly, strain gages for vertical wheel load are


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having minimal influence of lateral load. The cross talk between

vertical and lateral forces is kept to the barest minimum while

selecting the locations.

Wheatstone bridges are formed for vertical and lateral force

measurement channels. Measuring wheel supplied by Swede Rail has

two vertical and one lateral load sensing bridges per wheel. Sixteen

strain gage locations have been selected for vertical bridge with two

gages per arm and twelve locations for lateral bridge with three

gages per arm. This means that in one revolution of the wheel two

vertical and one lateral value would be obtained. Measuring wheel

supplied by AAR has one position channel in addition to above,

which indicates the rail wheel contact point.

Output of channels is taken from slip-ring device fitted on axle end

cap. AAR measuring wheel-set has slip-ring device on both ends of

the axle. Swede Rail measuring wheel-set has slip-ring device on one

end of the axle. Output signal lead from left wheel to right wheel is

transferred through a hole drilled in the axle. This has been done to

save the cost of slip-ring device.


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1) 100 TON CAPACITY FATIGUE TESTING SYSTEM

Introduction: To conduct general fatigue test on full scale

structures a closed loop electro-hydraulic servo controlled fatigue

testing system of 44 tone capacity with facility of testing full size

structures simulated service condition was installed in the fatigue

lab of RDSO in year 1972. This system was procured from MTS/USA.

Then because of the capacity and design constraint a new 100 tone

capacity fatigue system was procured from M/s Instorn U.K. and

installed in fatigue lab in 1997.

Salient Feature of the system: The test system basically consists of

closed loop electro-hydraulic computerized fatigue testing

equipment. It is provided with two hydraulic power supplies for

generating high hydraulic pressure required for producing the

desire forces. The high pressure hydraulic fluid at 210 Kg/cm2 is fed

to the hydraulic actuator to the maximum rate of 500 LPM, through

a servo-value. The actuator, which is a cylinder piston

arrangement, applies the compressive/tensile forces to the specimen

mounted on the test bed. The desired level of loading is achieved by

the controller in computerized control equipment of the system. A

command signal is fed to the input module which passes it on to a

servo controller. The desired dynamic wave form is provided by a

function generator. The controller sends electronic signal to the

servo valve to regulate its port opening in such a manner as to

achieve the desired load level. A feedback transducer introduced in

the system, sense the load applied to the specimen and sends a

proportional signal to the input module. Here, the feedback is

compared with the command and any difference in their

magnitudes or polarity is corrected through an electronic signal to


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the controller. With this arrangement any continuously varying

command is reproduced faith fully.

The desire load is achieved through under mentioned set of

dynamic actuators, one 50 tone and three 35 tone capacity reaction

frames mounted on rail type slotted bed of 7.5m*14m size.

Capabilities of system: System can provide dynamic and static

loadings on two axes simultaneously up to a maximum load of 100

tones in combination of above mentioned actuators. System has

facility to provide sine, square, haver-sine and triangle waveforms

of loading in dynamic mode.

Benefits: Rolling stock components like bogie frame and bolster of

Box- N wagons, Coaches and locomotives, Side bearer pads, friction

snubbers, brake beams, buffer springs, elastomeric pads, upper and


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lower spring pads, bridge stringers Composite material sleepers etc.

are regularly being tested on this machine.

S/No.

Type of

actuators

Quantity

Capacity

Stroke

Frequency w.r.t.

Displacement

Remarks Displacement

in mm

Frequency

in Hz

1.

Dynamic

Actuator

04Nos.

25 tones

+-

50mm

2.5 10 Actuators can work in

compressive as well

as in tensile mode

also

50 0.3

2. Dynamic

Actuator

02Nos.

10 tones

+-

50mm

2 10 Actuators can work in

compressive as well

as in tensile mode

also

50 0.5

2) 500 TONES CAPACITY STRUCTURAL

FATIGUE TESTING SYSTEM

Introduction:

Before Sep-2010, Fatigue testing lab of Testing Directorate was

equipped with 100 tones capacity fatigue testing system with a

maximum of 25 tones load actuators. This system was capable to

cater the general fatigue testing requirements of bogie frame and

bolster of existing wagon with maximum axle load of 22.82 tones.

Towards the process of development of high axle load wagons, RDSO

now is in process to develop the higher axle load wagons as per the

AAR standards. The bogies and bolsters of higher axle load wagons

are supposed to clear the accelerated fatigue testing on 453 tones

static and dynamic loadings as per the AAR test criteria. Hence this

system has been procured to cater the future testing requirements for

higher axle load wagons as per the AAR testing parameters.

Salient Feature of the system:


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This system is very high capacity equipment which can test the

specimen up to a load of 500 tones in static and dynamic modes.

But it has been designed in such a way that this huge system can be

utilized for testing of smallest components of rolling stock under 0.5

tone also, for its optimum utilization. The system is equipped with

two hydraulic power units with six pumps of 100 LPM in each HPU to

generate 3000 PSI hydraulic pressure on 1200 LPM discharge rate to

achieve the desire load through under mentioned set of dynamic

and static actuators and 500 tone capacity reaction frame on 10*10

meter “T” slotted bed plate, which can bear 600tones load.

The test system basically consists of closed loop electro-hydraulic

computerized fatigue testing equipment. It is provided with a

hydraulic power supply for generating high hydraulic pressure

required for producing the desired forces.


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The high pressure hydraulic fluid at 3000 PSI is fed to the hydraulic

actuator through a servo-value. The actuator, which is a cylinder

piston arrangement, applies the compressive/tensile forces to the

specimen mounted on the test bed. The desired level of loading is

achieved by the controller in computerized control equipment of the

system. A command signal is fed to the input module which passes it

on to a servo controller. The desired dynamic wave form is provided

by a function generator. The controller sends electronic signal to

the servo valve to regulate its port opening in such a manner as to

achieve the desired load level. A feedback transducer introduced in

the system, sense the load applied to the specimen and sends a

proportional signal to the input module. Here, the feedback is

compared with the command and any difference in their

magnitudes or polarity is corrected through an electronic signal to

the controller. With this arrangement any continuously varying

command is reproduced faithfully.

S/No.

Type of

actuators

Quantity

Capacity

Stroke

Frequency w.r.t.

Displacement

Remarks Displacement

in mm

Frequency

in Hz

1.

Dynamic

Actuator

04Nos.

25 tones

+-

50mm

2.5 10 Actuators can work

in compressive as

well as in tensile

mode also

50 0.3

2. Dynamic

Actuator

02Nos.

10 tones

+-

50mm

2 10 Actuators can work

in compressive as

well as in tensile

mode also

50 0.5

3. Static

Actuator

04Nos.

75 tones

300mm

Not applicable

Actuators can work

in compressive mode

only

The other important features are as under:


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1. Automotive test controller for controlling 8 actuators

upgradable up to 32 actuators.

2. 96 channel data acquisition system for on line stress

recording.

3. T-slot bed plate of 10m*10m size which can bear dynamic load

of 500 tones.

4. Four column portal frame of 500 tones capacity.

5. 6-point concentrator of 600 tones capacity and 3 point force

concentrator for combined load application of multiple

actuators.

6. Manual movement of ram of actuators through pendant.

7. Hydrostatic bearings have been provided in all the actuators

to bear maximum angular thrust.

8. Height of transverse beam can be adjusted through motorized

lifting device with laser beam safety monitoring system.

9. Heavy duty spring loaded roller clamp for easy sliding of cross

beam and actuators.

FOLLOWING FEATURES MAKE‟S THIS SYSTEM DIFFERENT FORM THE 100

TONE INSTRON MAKE OLD FATIGUE TESTING SYSTEM

1. This system can test the specimen up to 500 tones static and

dynamic load whereas old Instron machine is capable to test

up to 100 tones only.

2. A wide range of testing can be accomplished on these heavy

load actuators with +-125mm stroke whereas max. stroke of

Instron make actuators are +-50mm.


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3. Automotive test controller for controlling 8 actuators with

smart wave software capable of sequential loading between two

to all eight actuators on different load, different frequency

and different phase.

4. Facility to provide different waveforms of loading: sine, square,

ramp, rounded ramp, haver-sine and triangle.

5. Facility to provide vertical loading, lateral loading and

longitudinal loading simultaneously in different phase,

frequency and amplitude.

6. System can run in automatic mode on pre-programmed

loading test scheme.

7. 96 channel data acquisition system for on line stress recording

with auto channel balancing and auto calibration.

8. Facility of simultaneous acquisition and real time display of

feedback channels (position & load) of actuators with stress

value.

9. System to measure deflection up to 1 inch with accuracy of

0.001 inch.

10. Continuous running of the machine with feedback system

through SMS in case of any breakdown in the machine. This

facility will reduce testing time and manpower in other than

general shifts.

Capabilities:

1. This system can test the specimen upto 500 tones static and

dynamic loads.

2. Future heavy axle load wagons bogie, bolster and other

components can be tested as per AAR standards.


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3. Load deflection test and energy characteristics test can be done

on helical springs and rubber buffer springs through the machine,

since stroke of the actuators are 250mm.

4. Calibration of CBC can be done in tensile and compression mode

at 150 tones.

5. With the help of 96 channel data acquisition system on line stress

recording with auto channel balancing and auto calibration

which shows directly stress value. This reduces the testing time and

analysis time of data.

6. T-slot bed plate provides lot of flexibility while mounting the test

sample under the actuators.

7. Two hydraulic power supply units each provided with six pumps

with automatic flow control to save the power i.e. No of motors in use

will automatic are selected by the system depending upon the oil

flow requirement

Benefits: Accelerated Fatigue Testing of Bogies & Bolster of high axle

load wagons as per AAR specifications. This Fatigue Testing Machine

will help for design validation of high axle load wagons i.e. 25t

wagon & 32.5t etc. & other rolling stocks (coach & locos) also by

simulating field load conditions. This will also help to improve the

reliability of wagon bogie, bolster and other structure by assessing

the fatigue life of sub assembly.

STRESS MEASUREMENTS

The bogie is strain gauged at locations specified in the test scheme,

which are mostly linear gauges and a few three-directional Rossette

gauges. Each gauge (the arm in the case of Rossette gauges) fixed

on the bogies frame, functions as an active arm of Wheatstone

bridge for monitoring the strain / stress. The remaining three

gauges required to form the Wheatstone bridge, called the dummy


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gauges, are cemented on steel strips mounted on a junction box,

kept close to the bogie frame during the course of the tests.

Terminals of the bridge, thus formed, are connected to the recorder

(visicorder). During the stress recording in static condition, the

bogie is subjected to the desired load combinations and three sets of

readings are taken for every load combination. It is generally

noticed that the difference between the three readings is practically

negligible. Before conducting the dynamic stress measurement, the

bogie frame is subjected to the desired load combinations for at

least for 3 to 5 minutes and thereafter, the readings are taken.

FATIGUE TEST

The bogie frame is subjected to fatigue test by applying dynamic

load combinations as per test scheme. The load application is of

sinusoidal nature, which is achieved with the help of the function

generator available with control panel of the fatigue testing

equipment. Fatigue tests are carried out upto 10 million cycles. The

test frequency, with the stablised test set up, is achieved as 3 to 4 Hz.

All the dynamic load actuators are applying load at the same

frequency and in the same phase.

VERTICAL LOAD APPLICATION AND REACTION

The bogie frame is placed on the four vertical stools clamped with

the test bed. The loading is done with the help of load actuators,

each with the capacity of +10 or 25 t mounted on the two separate

main reaction frames capable of bearing 30 or 50 t force and

located longitudinally on both the sides of test bed, through two

loading beams placed at the ends of bolster which, in fact, is kept on

two specially designed steel tubes (in place of secondary springs)

placed in the spring seat guide located in the middle of the side

frames.

Reaction of the vertical load at axle box location is attained

through fabricated steel tubes placed between the bogie frame and

vertical stool at all the four locations. Specially designed load cells,


26

one each at all the four axle box locations, are inserted between the

stool and the steel tubes for equalizing the load distribution.

TRANSVERSE LOAD APPLICATION AND REACTION

A U-type clamp is mounted in the middle of the one of the side

frames on the existing bracket welded to the bogie frame. The

transverse load is applied centrally with the help of the +10 t

capacity dynamic actuators, held horizontally on the specially

designed brackets mounted on the test bed.

Transverse reaction is taken at all the axle box locations by suitable

reaction brackets clamped on the test bed.

TRACTIVE LOAD / BRAKING FORCE AND REACTION

Longitudinal loads, simulating tractive / braking load and their

reactions, are applied on the bogie frame separately. For the

purpose of braking force, loads are applied simultaneously at four

brake hanger locations, through two static jacks in the upward

direction, and through two pre-calibrated helical springs in the

downward direction. The tractive / braking loads are applied on

the two anchor links in the same direction through two static jacks

mounted horizontally on the two brackets, and their reactions are

taken in the opposite direction at the end of each side frame.

VISUAL EXAMINATION

Visual examination of the bogie frame is to be done regularly

throughout the test to check if any crack or deterioration in the

bogie frame, has got developed.


27

Gyrating Mass Brake Dynamometer

Brake Dynamometer Laboratory of RDSO has a dynamometer

supplied by M/s MAN, Germany.It was commissioned in 1974 for

study of brake material characteristics, development of new brake

materials, study of braking effect on wheels and quality control of

brake block.

The dynamometer has facilities for simulation of maximum road

speed of 245kmph with a one meter dia wheel. An axle load up to

25t. And maximum brake force of 6000kg pr brake block can also be

simulated. In addition to dry rail condition, spraying water

continuously on the wheel surface can also simulate wet rail

conditions.

For simulation of air impinging on the wheel, while the train is

running, blower fan having speeds of 750,1000 and 1500rpm has

been provided with the equipment and for extracting smoke, fumes

and dust of the brake blocks from the test space, exhaust fan having

3speeds of 750,1000 and 1500rpm is also provided.


28

The control room has a control desk, which accommodates, control

and indicator switches and a data acquisition system .A dial meter

displays the brake cylinder pressure Rotation speed of wheel and

braking time is digitally displayed.

Various brake characteristics e.g. speed, braking time, run out

revolution, brake torque, brake horse power, brake energy are

recorded by the data acquisition system. The temperature of the

Brake Block is also recorded in the data acquisition system, and the

temperature of the wheel is digitally displayed separately. The value

of mean coefficient of friction for individual brake applications is

also recorded in DAS.A graph of instantaneous µ versus speed is also

drawn for each brake application.

BRAKE BLOCK SAMPLES

FOR TESTING


29

Test Procedure And Allied Particulars:

Physical Check:

After the receipt of the brake block samples in the laboratory, these

are registered and identification numbers are stamped on each

brake block. These brake blocks are physically checked to ensure that

they match the wheel profile of the rolling stock for which testing is

to be done.

Bedding:

The brake blocks are then fitted on the dynamometer for bedding to

achieve about 80% of the block contact area .This exercise is

necessary to have a uniform distribution of brake block force over

the full brake block area during the tests. Bedding of the brake

block is done at a speed of 60km/hr and with a brake block force of

2000kg .During bedding a wheel temperature up to 100 degree

centigrade is maintained. After the contact area of the brake block

is needed to about 80%, tests are started.

Dry Tests:

1. Brake block are tested under dry condition at speeds of 40, 60,

80,100,110,120kmph with a brake block force of 3575kg.

2. After switching on the system with DC motor is first run at slow

speed. The motor is then accelerated to the desired rpm

corresponding to the required speed. The motor rpm is kept slightly

higher than the required braking speed. After attainment of the

slightly higher rpm, motor is switched off and brakes are applied at

corresponding speed with the help of „brake on‟ switch provided on

the control desk. Blower fan at a speed of 750 rpm and Exhauster

fan at a speed of 1000 rpm is normally kept running during the

tests.


30

3. Various parameters e.g. braking speed, braking time, run out

revolution, brake energy and mean coefficient of friction are

recorded on the data acquisition system.

4. Iron-Constantan thermocouples are embedded on the brake

blocks to monitor the brake block temperature.

5.Wheel temperature is, however, measured with a highly sensitive

contact less sensor mounted at the wheel rim very close to the

rubbing surface. This temperature is digitally displayed.

6.At the end of the each test series, the brake blocks are inspected in

respect of grooving, metallic inclusion, burning, non-uniform wear,

over heating etc. and surface condition of wheel tyre in respect of

polishing, pitting, flacking, cracking and other defects.

7.Brake blocks are weighed for wear as per test schemes.

Wet Tests:

1.As laid down in the ORE report No. B-64/RP10, continuous flow of

water at the rate of 14 liters per hour is allowed to fall on the top of

the wheel through small nozzles of 1-mm dia during wet tests. It

simulates the rainy season conditions.

2. During wet tests, blower is not used. This is to avoid flying away of

water falling on the top of the wheel.

3. Acceleration, running and braking at desired force are done in

the same manner as the dry tests.

4. During the wet tests, also inspection of both wheel and brake

blocks is done for any abnormally as per para 6 of dry test.

Drag Test:

1. After dry and wet tests on the brake blocks are over, the samples

are subjected to most severe type of braking, simulating controlling

of train on ghat section by applications of continuous brake.


31

2. The brakes are kept applied on the wheel for 20 minutes without

switching off the motor at a constant speed of 60 kmph. During drag

tests, torque equivalent to about 45 BHP is maintained. For

maintaining of constant torque, the brake force on the brake block

is recorded at every 60 sec. At the end of 20 minutes maximum

temperature attained by the wheel and brake blocks are recorded.

In case of brake blocks catching fire or any abnormality observed in

course of testing, further drag testing is stopped.

3. Immediately after above test, motor is shut off & brake block force

is increased to 2400 Kg and brakes are applied and various brake

characteristics are studied. During drag tests phenomena like,

emission of smoke and spark, formation of red band and flaming

etc. are recorded. At the end of the test, inspection of the wheel and

brake block is done to see any abnormality on the wheel and brake

blocks.

4. A WDM2 locomotive wheel having a diameter of 1092 mm was

used for these tests.

5. Gyrating masses having a moment of inertia of 286 kgfms2.

Excluding that of revolving wheel and sub-axle were engaged to

simulate an axle load of 18.8t.


32

The laboratory is equipped with a Test Rig having the complete

pneumatic circuits of 192 wagons and 30 coaches with twin pipe air

brake system. Three locomotive control stands can be used anywhere

in the formation, with varying compressed airflow rate up to 16 kl

per minute with the help of 7 compressors. Data acquisition and

analysis is completely computerised. The laboratory is equipped with

a single car test rig and an endurance test rig for distributor valves.

Brakes are essentially meant for controlling the speed and stopping

of train. Different brake systems are prevailing in the requirements

laid down by each Railway Administration. However, whatever may

be the brake system it should have the following basic requirements :

Should be automatic and continuous i.e., at the event of train

parting brake should apply.

Shortest possible emergency braking distance.

Maximum possible brake force.

Shortest brake application time.


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Shortest brake release time.

Low exhaustibility of brake power under continuous or repeated

brake application.

Minimum run-in and snatch action during braking.

TYPES OF BRAKE SYSTEM

Vacuum brake

Single or Twin pipe graduated Air brake system

Electro-Pneumatic brake

AIR BRAKE SYSTEM

Single pipe graduated release air brake system is used in air braked

wagons. The main components of this system are :-

Distributor valve

Brake Cylinder

Auxiliary reservoir

control reservoir

Brake pipe and feed pipe

Flexible House Coupling

Rubber House pipe

Brake pipe which runs throughout the length of the train has air

pressure at 5 kg/sq.cm. The compressed air is supplied by compressor

/expresser in the locomotive and the brake pipes of adjacent wagons

are joined by using flexible coupling. For application of brakes, the

air pressure is reduced. The drop in pressure being proportional to

the braking effort required. The drop in pressure is sensed by the


34

distributor valve (DV) which allows compressed air from the

auxiliary reservoir into the brake cylinder and results in brake

application through brake shoes,release of brake taking place by

normalizing by A-9and air from the brake cylinder released

symlatenaus brake pipe pressure increased up to 5 kg. The brake

cylinder develops a maximum air pressure of 3.8kg/sq.cm.

During application of brakes the auxiliary reservoir gets

disconnected from the brake pipe. The auxiliary reservoir has

capacity of 100 liters capacity whereas control reservoir is of 6 liters

capacity. A fig of Single pipe graduated release air brake system is

given below-

TYPES OF AIR BRAKE SYSTEM

1. Direct Release Air Brake System – AAR Standard

In direct release air brake system, the release of brakes depends

upon complete buildup of BP pressure. Since the pressure differential

between brake pipe and the Auxiliary reservoir controls the both

application and release, the release pressure once initiated cannot

be stopped except by reduction in brake pipe pressure below AR

pressure, which if resorted to frequently before the Auxiliary

Reservoir is charged fully, will results in the exhaustibility of the

brake system.

The main advantage of direct releaser system is that it has faster

release compared with the graduated release system. The addition

of emergency valve to the triple valve in the direct release system

permits, a very rapid application by venting the train pipe locally at

every vehicle.

2. Graduated Release Air Brake System – UIC Standard

In graduated release system, the Brake cylinder pressure varies

according to brake pipe pressure. The brakes are fully released when

the BP pressure is fully charged. The graduated release system is

inexhaustible as the BC pressure is related all times to the pressure in


35

brake pipe, full release of the brakes being obtained when brake pipe

have been fully charged.

The main advantage of Graduated release system is quick release of

brake system and reduced release time.

The graduated release brakes are considered more suitable for

passenger stock because of inherent smooth release function

promoting riding comfort. The graduated release system conforms to

UIC regulation, which lays down a release time of 45-60 seconds.

In the graduated release system the application of the brake can be

accelerated with brake accelerator valves which can be attached to

the main control valve.

WORKING PRINCIPLE OF AIR BRAKE SYSTEM

In air brake system compressed air is used for operating the brake

system. The locomotive compressor charges the Feed pipe and Brake

pipe throughout the length of the train. The feed pipe is connected to

the Auxiliary reservoir and the brake pipe is connected to the

distributor valve. AR is also connected to the BC through DV. The

brake application takes place by dropping the air pressure in the

brake pipe by the driver from locomotive by the application of A-9

valve. Following three activities involved in this system:

1. Charging

Brake pipe throughout the length of the train is charged with the

compressed air at 5 Kg/cm2

.

Feed pipe throughout the length of the train is charged with

compressed air at 6 Kg/cm2

.

Control reservoir is charged to 5 Kg/cm2

.

Auxiliary reservoir is charged to 6 Kg/cm2

.in case of twin pipe and

5 Kg/cm2

in case of single pipe

2. Brake Application


36

For brake application, the brake pipe pressure is dropped by venting

air from driver‟s brake valve subsequently the following action takes

place:

The control reservoir is disconnected from the brake pipe.

The DV connects the AR to the brake cylinder and the brake

cylinder piston is pushed outwards for application of brakes

The AR is towards continuously charged from the feed pipe at 6

Kg/cm2

air pressure.

3. Brake Release Stage

Brakes are released by recharging brake pipe to 5 Kg/cm2

through

the driver‟s A-9 brake valve.

The DV isolate the BC from AR.

The BC pressure is vented to atmosphere through DV and the BC

piston moves inwards.

Description Reduction in BP Pressure

Full Service Brake application 1.3 to 1.6 Kg/cm2

Emergency Brake application Brake pipe is fully exhausted to

zero pressure

BASIC REQUIREMENTS TO DESIGN THE BRAKE SYSTEM

While designing the brake system, the following are the basic

requirements, which kept in the mind:

Brake system should be in operation and reliable.

Should be continuous and being applied to each vehicle

in the train.


37

Should be instantaneous in action and capable of being

applied from the driver‟s CAB.

Should be self-employing in case of train parting.

Should have minimum number of parts.

Should apply equal forces on each wheel.

Should have maximum possible braking force.

Should have shortest possible emergency braking

distance.

Should have shorter brake application time.

Should have shorter brake release time.

Low exhaustibility of brake power under continuous

repeated brake application.

Ease in maintenance.

ADVANTAGES OF AIR BRAKE SYSTEM

It has higher rate of propagation.

It has shorter brake application and release time.

Brake fade does not take place, therefore, the train can

be held on down grade without any difficulty for a

considerably longer period.

It has higher degree of reliability, controllability and

maintainability.

Rigging is simple and entire equipment‟s are lighter and

required less space.

Simple maintenance through calling for a higher degree

of skill.


38

Provide for higher operating speed.

Caters for smaller emergency braking distance.

Compressed air can be stored to higher-pressure

differential.

Salient Features of Air Brake System (BMBS)

The brake system provided on the wagons is single pipe graduated

release system with automatic two stage braking. Its operating

principle is as follows: -

Schematic layout of single pipe graduated release air brake system

as provided on the wagons is shown in sketch below. Brake pipe runs

through the length of wagon. Brake pipe on consecutive wagons in

a train are coupled to one another by means of hose coupling to

form a continuous air passage from the locomotive to the rear end

of the train. Brake pipe is charged to 5 kg/cm2

through the

compressor of the locomotive.

The wagons are provided with automatic two-stage Automatic

Brake Cylinder Pressure Modification Device to cater for higher

brake power in loaded condition instead of the conventional

manual empty load device. With the provision of this, brake

cylinder pressure of 2.2 kg/cm2

is obtained in empty condition and

3.8 kg/cm2

is obtained in the loaded condition. To obtain this a

change over mechanism, “Automatic Brake Cylinder Pressure

Modification Device” (APM) is interposed between the under-frame

and side frame of the bogie. The mechanisms gets actuated at a

pre-determined change over weight and change the pressure going

to the brake cylinder from 2.2 kg/cm2

to 3.8 kg/cm2.

and vice-versa

For application of brake, air pressure in the brake pipe is reduced by

venting it to the atmosphere from drives brake valve in the

locomotive. The reduction of the brake pipe pressure, positions the

distributor valve in such a way that the auxiliary reservoir is

connected to the brake cylinder through APM device and thereby


39

applying the brake. During full service brake application, a

reduction of 1.4 to 1.6 kg/cm2

takes, a maximum brake cylinder

pressure of 3.8 kg/cm2

in loaded condition and 2.2 kg/cm2

in empty

condition is developed. Any further reduction of brake pipe pressure

has no effect on the brake cylinder pressure. During emergency

brake application, the brake pipe is vented to atmosphere very

quickly; as a result the distributor valve acquires the full application

position also at a faster rate. This result in quicker built up of brake

cylinder pressure but the maximum brake cylinder pressure will be

the same as that obtained during a full service brake application.

For release of brakes, air pressure in the brake pipe is increased

through driver‟s brake valve. The increase in the brake pipe pressure

results in exhausting the brake cylinder pressure through the

Distributor valve. The decrease in the brake cylinder pressure

corresponds to the increase in the brake pipe pressure. When the

brake pipe pressure reaches 5kg/cm2

, the brake cylinder pressure

exhausts completely and the brakes are completely released.

Brake Cylinder with built-in Double acting Slack Adjuster

The brake cylinder receives pneumatic pressure from auxiliary

reservoir after being regulated through the distributor valve and

Automatic Brake Cylinder Pressure Modification Device develops


40

mechanical brake power by outward movement of its piston and

ram assembly.

The piston rod assembly is connected to the brake shoes

through a system of rigging levers to amplify and transmit the brake

power. The compression spring provided in the brake cylinder brings

back the rigging to its original position when brake is released.

Automatic Brake Cylinder Pressure Modification Device (APM)

Load sensing device is interposed between bogie side frame of casnub

bogie and the under frame of wagons. It is fitted on one of the

bogies of the wagon. It is fitted for achieving 2-stage load braking

with automatic changeover of brake power.

Salient feature of BMBC

External slack adjuster is removed/eliminated.

Higher composition brake blocks of „K‟ type have been

used.

Advantage of BMBS

Higher service life of brake block.

Elimination of slack adjuster shall result in lesser cases of

brake binding and consequent from detention.

Simplified brake rigging shall reduce maintenance

inputs in carriage maintenance depots.

Reduce level of noise during braking.

Saving in energy in haulage on account of weight

reduction of coaches.

Due to elimination of levers the brake rigging efficiency

increased to 90% against 80% in U/F mounted brake

system.


41

AIR BRAKE SYSTEM TEST RIG:

INTRODUCTION:

Air brake test rig is, with a facility for simulation of field condition

for 132 wagon freight train & 30 coach passenger train with single

and twin pipe air brake system with data acquisition facility on 234

channels only. This test rig has also facility to acquire data of BP,

BC at every wagons on 58 wagon‟s freight train and for 30 coach‟s

passenger train with BP, FP, BC, & MR on three locomotive along

with facility to measure air flow at four points on whole test rig.

The test rig is designed to measure real time pressure in brake pipe,

Feed pipe, brake cylinders in coaches and wagons and BP,FP,BC,MR,

and air flow in three multiple locomotives on 234 channels data

acquisition system with a sampling rate of 100 sample per second

during initial charging of brake system and application and

release of brakes.

The application software is in LABVIEW and Data Acquisition system

is also of National Instrument. The software is such that it can

calculate the application and release time of any intermediate

coach/wagon with the help of 0.08% accuracy (very high accuracy)

GE Druck /Germany make pressure transmitters. The exact flow of air

is cross checked by flow meter connected in BP and MR line. It can

check the application and release time with flexible number of

coach/wagon connected with loco within the maximum limit.

CAPABILITIES OF TEST RIG:

This test rig is being used to test the performance of brake valves and

equipments on the simulated train consist in stable condition to

study on under mentioned scopes.

1. Braking characteristics of freight train up to 132 BOXN

wagon with single and twin pipe system.


42

2. Passenger train up to 30 coaches with twin pipe system.

3. Effect of change in design of loco brake system on braking

characteristics of passenger and freight train.

4. Brake characteristics of freight and passenger train with

multiple loco operation.

5. Optimum location of locos in long freight train.

6. Effect of changes in design of distributor valve on brake

characteristic of freight & passenger train.

7. Brake characteristic in case of train parting.

8. Effect of leakage rate on brake system.

9. Effect of over charge feature on train operation.

10. Optimum compressor & reservoir capacity for various

train lengths.

11. Indication to driver in case of train parting.

12. Performance test of distributor valves.

13. Performance test of all valves and equipments of loco,

coaches and freight brake system.

14. Effect of EOTT on train brake operation.

15. Effect of Automatic Brake Unit of Anti-Collision device of

locomotive on Brake operation.


43

Twin Pipe Air Brake System For Coaches

Single Pipe Air Brake system For Wagons

rdso training report -navin dixit

Engineering

railway testing

rdso summer training

standards organization

development of railway

status of rdso

research designs

fatigue testing laboratory

new organization