handbook on installation & maintenance practices of

GOVERNMENT OF INDIA

MINISTRY OF RAILWAYS

Handbook on

Installation & Maintenance practices of

Electric Point Machine 220 mm throw

With Clamp type lock for Thick Web Switch

End Users : SSE/JE (Signal) & Signal Maintainers

CAMTECH/S/PROJ/2020-21/SP8/3.0

December 2020

Maharajpur, Gwalior (M.P.) – 474005

ii

Handbook on

Installation & Maintenance practices of

Electric Point Machine 220 mm throw With Clamp type lock for Thick Web Switch

CAMTECH/S/PROJ/2020-21/SP8/3.0

December 2020

iii

Foreword

The traffic density has increased tremendously over the years on Indian

Railways and along with it high speed trains have also been introduced. For safe

and efficient operation of high speed rolling stock various means such as higher

section of rail, high power locomotives and high speed turnouts have been

inducted. High speed train projects on some identified routes are also in the

pipeline. To meet the requirements of point operation on such high speed turnouts

Electric Point Machines 220 mm throw with additional safety feature of clamp

type lock are being installed. CAMTECH has prepared this handbook for Signal personnel to get them

acquainted with installation and maintenance practices of Electric Point Machine

220 mm throw. I am confident that this handbook will help them in installation and

maintenance of this machine under their jurisdiction.

CAMTECH Gwalior Jitendra Singh

Date: Principal Executive Director

iv

Preface

On Indian Railways, high speed trains such as Rajdhani Express, Shatabdi

Express and Gatiman Express are in operation and new high speed corridors are

proposed to cater for demand of increasing traffic density. In projects like

dedicated freight corridor, high speed turnouts with thick web switch are being

installed for which Electric Point Machine of 220 mm throw with clamp type

locking is provided.

CAMTECH has prepared this handbook for the guidance of Signal

personnel regarding correct installation and efficient maintenance of Electric Point

Machine for Thick web Switch installed in their section. Installation as per

modified RDSO drawing has also been covered in the handbook.

We are sincerely thankful to Signal Directorate RDSO Lucknow, West

Central Railway, M/s Vossloh Cogifer Signalling India Pvt. Ltd., Bhilai and S&T

personnel of Indian Railways who helped us in preparing this handbook by

providing valuable information.

Since technological upgradation and learning is a continuous process, you

may feel the need for some addition/modification in this handbook. If so, please

give your comments on email address [email protected] or write to us at

Indian Railways Centre for Advanced Maintenance Technology, In front of

Adityaz Hotel, Airport Road, Maharajpur, Gwalior (M.P.) 474005.

CAMTECH Gwalior Dinesh Kumar Kalame

Date: Jt. Director (S&T)

mailto:[email protected]

v

Table of Contents

Foreword ...................................................................................................................................................... iii

Preface ......................................................................................................................................................... iv

Table of Contents .......................................................................................................................................... v

Issue of Correction Slip ............................................................................................................................... vii

Disclaimer................................................................................................................................................... viii

Our objective ................................................................................................................................................ ix

CAMTECH Publications.................................................................................................................................. x

1 Introduction ........................................................................................................................................... 1

Salient features of TWS ............................................................................................................................. 1

2 Clamp type lock and its advantages ...................................................................................................... 1

3 Spring setting device (SSD) .................................................................................................................. 2

4 Modification in design of Spring Setting Device to prevent track circuit failures ................................ 4

5 Main Parts ............................................................................................................................................. 6

6 Main parts of Clamp Lock and Functions ............................................................................................. 6

Working of Clamp Lock ....................................................................................................................... 7

7 Installation guidelines ........................................................................................................................... 7

7.1 Installation as per RDSO drawing no. RDSO/S3454 .................................................................... 7

7.2 Installation as per RDSO drawing no. RDSO/S3454 ALT –A Ver.1.0 ...................................... 16

8 Adjustment.......................................................................................................................................... 17

9 Testing................................................................................................................................................. 18

9.1 Obstruction Test.......................................................................................................................... 18

9.2 Insulation Test ............................................................................................................................. 18

10 Maintenance ................................................................................................................................... 19

11 Troubleshooting .............................................................................................................................. 20

12 Do’s & Don’ts ................................................................................................................................. 22

13 Tools & Spares ................................................................................................................................ 22

vi

14 Summary ......................................................................................................................................... 24

15 References ....................................................................................................................................... 27

16 Annexure I : Modified RDSO design for Spring Setting Device (SSD) of Thick Web Switch (Drg.

No. RDSO/T 6216 ALT-4) ......................................................................................................................... 28

17 Annexure II : RDSO Drawings for Ground connections of Electric Point Machine 220 mm stroke

with Clamp Lock for Thick Web Switch (TWS) (Drg. No. RDSO/S-3454) ................................................... 28

18 Annexure III : Modified RDSO Drawings for Ground connections of Electric Point Machine 220

mm stroke with Clamp Lock for Thick Web Switch (TWS) (Drg. No. RDSO/S-3454 ALT–A Ver. 1) ............. 28

vii

Issue of Correction Slip

The correction slips to be issued in future for this handbook will be numbered as follows:

CAMTECH/S/PROJ/2020-21/SP8/3.0# XX date .......

Where “XX” is the serial number of the concerned correction slip (starting from 01 onwards).

CORRECTION SLIPS ISSUED

Sr. No. of

Correction

Slip

Date of

issue

Page no. and Item

No. modified

Remarks

viii

Disclaimer

It is clarified that the information given in this handbook does not

supersede any existing provisions laid down in the Signal Engineering

Manual, Railway Board and RDSO publications. This document is not

statuary and instructions given are for the purpose of guidance only. If

at any point contradiction is observed, then Signal Engineering Manual,

Railway Board/RDSO guidelines may be referred or prevalent Zonal

Railways instructions may be followed.

ix

Our objective

To upgrade Maintenance Technologies and Methodologies and achieve

improvement in Productivity and Performance of all Railway assets and manpower

which inter-alia would cover Reliability, Availability and Utilisation.

If you have any suggestion & any specific comments, please write to us:

Contact person : Director (Signal & Telecommunication)

Postal Address : Centre for Advanced Maintenance Technology,

Maharajpur, Gwalior (M.P.) Pin Code – 474 005

Phone : 0751 - 2470185

Fax : 0751 – 2470841

Email : [email protected]


x

CAMTECH Publications

CAMTECH is continuing its efforts in the documentation and up-gradation of information on

maintenance practices of Signalling & Telecom assets. Over the years a large number of

publications on Signalling & Telecom subjects have been prepared in the form of handbooks,

pocket books, pamphlets and video films. These publications have been uploaded on the internet

as well as railnet.

For downloading these publications

On Internet:

Visit www.rdso.indianrailways.gov.in

Go to Directorates → CAMTECH → Publications for download → S&T Engineering

Or http://www.rdso.indianrailways.gov.in/view_section.jsp?lang=0&id=0,2,17,5025

On Railnet:

Visit RDSO website at 10.100.2.19

Go to Directorates → CAMTECH → Publications → S&T Engineering

Or

http://10.100.2.19/camtech/Publications/CAMTECH%20Publications%20Online/CAMTECHMai

n.htm

A limited number of publications in hard copy are also available in CAMTECH library which can

be got issued by deputing staff with official letter from controllong officer. The letter should be

addressed to Director (S&T), CAMTECH, Gwalior. For any further information regarding

publications please contact:

Director (S&T) – 0751-2470185 (O)(BSNL)

SSE/Signal - 7024141046 (CUG)

Or

Email at [email protected]

Or

FAX to 0751-2470841 (BSNL)

Or

Write at

Director (S&T)

Indian Railways Centre for Advanced Maintenance Technology,

In front of Hotel Adityaz, Airport Road, Maharajpur,

Gwalior (M.P.) 474005

http://www.rdso.indianrailways.gov.in/

http://www.rdso.indianrailways.gov.in/view_section.jsp?lang=0&id=0,2,17,5025


CAMTECH/S/PROJ/2020-21/SP8/3.0 1

Electric Point Machine 220 mm throw for Thick Web Switch December 2020

Electric Point Machine 220 mm throw

With Clamp type Lock for Thick Web Switch

1 Introduction

The traffic density is increasing day by day on Indian Railways and to increase the section

capacity higher speeds of trains are always aimed at. To meet this demand higher power

locomotives were developed and high speed turnouts i.e. more than the existing 1 in 12

turnouts are being laid. In most of the new works such as the work of freight corridor (third

line) high speed turnouts with higher section of rails i.e. Thick web switch (TWS) with 60

Kg rails are being installed. For operating TWS, the existing design of Electric Point

Machine was modified with the incorporation of clamp type lock for additional safety.

Salient features of TWS

The crossing angle has been broadened so that the train negotiating at higher speeds does

not pose any danger.

The switch opening is of 160 mm as against of 115 mm of ordinary cross over.

The web of the switches is made thicker to make than them strong enough to withstand load

of train at high speeds.

2 Clamp type lock and its advantages

A CLAMP LOCK clamps together the closed switch against the stock rail and achieves the

locking of the switch. For the working of clamp lock, the throw bar of point machine is

provided with a total of 220 mm stroke the distribution of which is as given below:

60 mm for the unlocking,

100 mm for the throwing of points and

60 mm for the locking of closed switch.

Advantages:

(a) It ensures and proves the proper setting of switch rail against stock rail.

(b) Due to the 160 mm opening of thick web switch (TWS) at toe the clearance at junction

of rail head (JOH) is 60 mm. This prevents the repeated striking of the open switch at

junction of rail head (JOH) by inner side of the wheel, which in conventional switches

leads to chances of under wheel flashing.

(c) It prevents vibration caused in the switch due to train movement which in turn prevents

disturbance to detection and control contacts assembly unit directly. In conventional

switches this leads to reduction in efficiency of the unit.

(d) Due to complementary tapers in switch and stock rail, the switch rail toe fits underside

the stock and therefore the wheel of the train engages the switch rail well after 6" from

toe. Therefore, damage and wear and tear of the switch is prevented.

(e) Provides direct locking between tongue rail and stock rail in closed position.

(f) Firmly holds the tongue rail in the open position. Checks any relative movements

between tongue and stock rail

(g) It ensures and proves the proper setting of switch and stock rail.



3 Spring setting device (SSD)

(a) In a TWS turnout, no stretcher bar is used and hence switches are able to move

independently.

(b) A spring setting device (SSD) is provided at junction of Rail head (JOH), in lieu of

stretcher bars, to assist in proper setting of switch upto JOH, which is placed between

sleeper number 13 and 14.

(c) Adjustment of locking is done by means of packing shims between switch rail and stock

rail bracket. Three each of 1 mm and one of 0.5 mm shims are provided for each switch.

Need for SSD

(Reference: www.binametalway.com of M/s Bina Metal Way Pvt. Jamshedpur)

Railways are increasingly using curved switches in turnouts, since they enable smoother

passage and also permit higher speeds. In curved switches, the distance from Actual Toe

(AT) up to Junction of Rail Heads (JOH), where the machining of tongue rail head ends, is

much longer as compared to the corresponding distance in straight switches which were

used earlier. As a consequence, the tongue rail in curved switches is comparatively much

slender in the stretch from AT to JOH.

When a throw is given to the tongue rail of curved switches at AT, the flange way

clearance between the open tongue rail and the corresponding stock rail near JOH is of the

order of 35 to 50 mm only. This is much lesser than the minimum clearance of 60 mm

(approx) needed for smooth passage of the wheel-flange through open switches. As such,

back-face of wheels graze the back-face of tongue rails when vehicles negotiate open

switches, thus causing rattling of tongue rail as also wear on its back-face. While wear on

the gauge-face of tongue rail is quite usual, the wear caused on the back-face of tongue

rails distorts the geometry of switch when such a worn tongue rail is closed against its

stock rail.

Another consequence of the slenderness of tongue rails of curved switches is non-butting

of the closed tongue rail against its corresponding stock rail at JOH, where a gap of 10 to

25 is observed between the two rails. This gap causes gauge variation in switch portion and

vibration of tongue rail when wheel-flange presses against the gauge-face of tongue rail.

Curved switches are used in preference to straight switches basically for enabling smoother

and faster travel. Therefore, there is a greater need to ensure proper alignment, gauge,

fitment etc in curved switches. The problems noticed in curved switches as discussed

above, defeat the very purpose of their introduction.

SSD have been designed to address this particular problem. When this device is located

near and connected to the Last following Stretcher Bar of the switches, it ensures the

following:

A minimum flange way clearance of 60 mm (approx) at JOH between the open tongue

rail and its stock rail.

The butting of closed tongue rail against its stock rail from AT to JOH.



Figure 1 : IRS-Clamp type Point Machine Layout with TWS

Function of SSD

(Reference : IRICEN Pune's publication on Turnout - Laying, Inspection,

Maintenance, September 2014)

For best performance, tongue rail should bear against the stock rail from Actual Toe of

Switch (ATS) to Junction of Rail Head (JOH). However achieving setting of tongue rail up

to JOH may be difficult in the field. Since the stretcher bar is fixed to the tongue rail while

the tongue rails are at half throw, it sets a force in tongue rail, when it is pressed against any

stock rail. Point machine presses the tongue rail against one of the stock rails at the ATS but

in the absence of any force near JOH, tongue rail opens out at this location.

Since on Indian Railways there is no

means to provide force on tongue rail at

JOH, Spring Setting Device has been

developed which provides thrust on the

tongue rail, near JOH so that the tongue

rail bears well against stock rail. As per

present orders, only RDSO approved

design of SSD are to be used.

Figure 2: Spring Setting Device (SSD) with

cover open



Spring setting device is provided with springs which initially opposes the movement of

tongue rail at the time of beginning of change of direction till the time tongue rail crosses

half throw. After passing a particular position, direction of force provided by spring changes

and it provides a force to press the tongue rail which is to be set for train movement. Thus it

presses tongue rail against the stock rail at JOH. Provision of Spring Setting Device may

take care of the problems such as tongue rail not fully bearing against stock rail up to JOH.

It will also take care of inadequate clearance of open tongue rail and stock rail at JOH,

which is particularly more pronounced in case of 1 in 12 turnouts. SSD is able to provide

opening of 60 + 2mm of tongue rail at JOH. It also takes care of rattling of tongue rail under

passage of wheels.

4 Modification in design of Spring Setting Device to prevent track

circuit failures It has been observed that present design of SSD is prone to track circuit failures due to

existing insulation arrangement in SSD arm (connecting arm). These failure are mainly due

to iron dust falling over insulation and frequent crushing of very thin layer of insulation. To

prevent track circuit failures, insulation has been provided at a new location in Agra and

Prayagraj Division of North Central Railway on trial basis. This trial has drastically reduced

the track circuit failures. RDSO Track Directorate in consultation with Signal Directorate

has also issued revised drawing for SSD {Refer Annexure I - Drawing No. RDSO/T-6216

Figure 3: Sketch showing Spring Setting Device (SSD)



(ALT-4) dated 04.10.2019}. Meanwhile the following arrangement can be done locally till

SSDs with new design are supplied:

A 50 mm piece is cut in the SSD Arm (connecting rod) and links are welded at both ends

similar to that provided in roding joints as shown in the figure below:

Insulation plate is provided between the two links and fixed through nuts and bolts with

nylon washers.

Figure 4: 50 mm piece cut from SSD arm and links welded

Figure 5 : Provision of insulation in SSD arm



5 Main Parts

Main parts of point machine are:

(a) DC series split field Motor within built reduction gear unit.

(b) Transmission assembly.

(c) Throw rod, lock slides and detection slides.

(d) Detection and control contact switch Assembly.

(e) Cast iron Case with cover.

(f) Crank handle.

Operating data as per IRS: S 24/2002 - Amendment No. 1

Motor- DC series split field

Throw of point machine - 220 mm + 4 / -1

Time of operation (Max.) - 5.0 sec.

Current consumption - < 5.5 Amp.

Rated voltage - 110 VDC

Max. Throw – 450 Kg.

Slipping load - < 580 Kg.

Stalling load (Min.) - 1000 Kg.

6 Main parts of Clamp Lock and Functions (a) Locking bar (L.H.)

(b) Locking bar (R.H)

(c) Insulating plates

(d) Locking washers

(e) Locking arms

(f) Stopper

(g) Drive lug

Locking bar (L.H) and locking bar (R.H) are joined with insulating plate and locking washer

at both ends are inside of both switch rail and stock rail brackets. Its movement depends on

the stroke of drive rod, which is attached to one end of locking bar by drive rod.

Locking arm assembly: it consists of L.H. and R.H. Arms. Its main function is to lock and

unlock the clamp. It is attached with the stock rail with the help of bracket and to the lock

bars with guide.



Working of Clamp Lock

Initially the point is lying in normal and right hand switch is locked whereas left hand

switch is open with an opening of 160 mm.

When the lockbar is pulled by the electric point machine the open switch starts moving

towards the stock rail.

The lock bar’s initial stroke of 60 mm is used to unlock the clamp lock at closed switch.

After unlocking of the clamp lock the closed switch starts opening.

When the lockbar travels 160 mm, open switch completes the stroke and closes fully with

stock rail.

However, the closed switch which had started opening, opens up to about 100 mm only.

When the lock bar further travels and completes the total stroke of 220 mm, the open

switch completely closes with the stock rail and gets locked.

The earlier closed switch which has opened upto 100 mm now further completes the

opening to 160 mm.

To summarize the above operation, 220 mm throw of Point machine is distributed as

follows:-

(a) First 60 mm throw of Point machine

(i) Unlocking of Closed switch and

(ii) Open switch moves 60 mm towards its stock rail.

(b) Next 100 mm throw, both switches move

(i) Closed switch opens by 100 mm and

(ii) Open switch completes (60 mm+100 mm) =160 mm and it is now closed.

(c) Last 60 mm throw

(i) 100 mm Opened switch further movers to 60 mm = (100 mm+60 mm)=160 mm.

(ii) Locking of Closed switch by 60 mm.

7 Installation guidelines The installation of IRS Point machine 220 mm throw was earlier done as per RDSO

drawing no. RDSO/S3454. RDSO has now issued a new drawing no. RDSO/3454 ALT-A

Ver. 1 vide letter no.STS/E/PM/220 mm Vol-I dated 07.11.2019. Details of installation as

per both drawings are given in following sections.

7.1 Installation as per RDSO drawing no. RDSO/S3454

The procedure for IRS Point Machine with Clamp Lock and Ground Connection

arrangement 60 Kg (with Thick Web Switch) for B.G as per RDSO as per RDSO DRG.

No. RDSO/S3454 is as follows (Refer Annexure II) :

(A) Preparatory steps

(a) Bring the toe of switch at 32 mm in advance of centre line of sleeper No.3 and distance

between sleeper No.3 and 4 to 685 mm. (centre-line to centre-line). (As per RDSO



drawing no. RDSO/S 3454 Sleeper spacing has been modified as 685 mm instead of

745 mm vide ALT 4 dated 28.12.2001).

(b) Ensure that insulated gauge tie plate is provided on sleeper No. 3.

(c) Remove all leading and following stretcher bars.

(d) Provide spring setting device of approved design at junction of rail head (JOH).

(e) Maintain gap at junction of rail head (JOH) not less than 57 mm for every flange way

clearance.

(B) Marking & drilling holes for Clamp Lock Assembly

(a) Stock rail

(i) For marking holes in stock rails mark centre-line on the web of stock rail at the height of

76 mm from bottom of stock rail up to the length of 550 mm from toe.

(ii) Mark centre punch to the length of 450 mm for 1st hole and 530 mm for 2

nd hole from the

edge of the tongue rail toe.

(iii) Ensure that there is a gap of 80 mm between both the holes (Centre-line to Centre-line of

the holes) as shown in figure given below.

(iv) Drill two holes of 22mm dia in the web of both stock rails for fixing stock rail brackets.

Figure 6: Marking & drilling of holes in stock rail for Clamp Lock Asembly



Figure 7: Cross-section showing position of holes in stock rail for Clamp lock assembly

(b) Tongue rail (i) For marking in tongue rails, mark centre-line on web of the tongue rail at the height of

55 mm from bottom of tongue rail up to the length of 500 mm.

(ii) Mark centre punch to the length of 428 mm for first hole and 498 mm for second hole

from toe.

(iii) Ensure that there is a gap of 70 mm between both holes (Centre-line to centre-line of the

holes).

(iv) Drill two holes of 22 mm dia in the web of the tongue rail for fixing switch rail bracket.

Figure 8: Sketch showing view of holes in stock rail for Clamp Lock Assembly



Figure 9: Marking & drilling of holes in tongue rail for Clamp Lock Assembly

Figure 10: Cross-section showing height of the holes in tongue rail

Figure 11: Sketch showing holes in tongue rails for Clamp Lock Assembly



(C) Marking & drilling holes for ground connections (Lock and detector rods)

(a) If point machine is connected to Left hand- side.

(i) First make the centre-line in the foot of both tongue rails up to 350 mm length from toe.

(ii) Mark centre punch up to the length of 148 mm for first hole and 328 mm for second hole

from the toe in the LH tongue rail.

(iii) Mark punch up to the length of 200 mm for first hole and 272 mm for second hole from

toe in RH tongue rail.

(iv) Drill two holes of 24 mm dia in the foot of the switch rail at the markings for connecting

lock rod and detector rods.

Figure 12 : Marking & drilling of holes in LH Tongue rail for ground connections (Point

machine on

LHS)

Figure 13: Marking & drilling of holes in RH Tongue rail for ground connections (Point

machine on LHS)



(b) If point machine is connected to Right hand- side.

(i) First make the centre-line in the foot of both tongue rails up to 350 mm length from toe.

(ii) Mark punch up to the length of 148 mm for first hole and 328 mm for second hole

from toe in RH tongue rail.

(iii) Mark centre punch up to the length of 200 mm for first hole and 272 mm for second

hole from the toe in the LH tongue rail.

(iv) Drill two holes of 24 mm dia in the foot of the switch rail at the markings for

connecting lock rod and detector rods.

Figure 15: Marking & drilling of holes in LH Tongue rail for ground connections (Point

machine on RHS)

Figure 14: Sketch showing holes for ground connections in tongue rails (Point

machine on LHS)



Figure 16: Marking & drilling of holes in RH Tongue rail for ground connections (Point

machine on RHS)

Figure 18: Ground connections for RH Tongue rail and holes for ground connections

in LH Tongue rail

Figure 17: Sketch showing holes for ground connections in tongue rails (Point

machine on RHS)



(D) Connection for Clamp Point locks

(i) Connect the stock rail bracket to the stock rail as in Fig. below.

Figure 19: Connecting Stock rail bracket

(ii) Assemble the LH and RH Lock Arm assemblies

(iii) Now fix tongue rail bracket with the lock arm assembly

(iv) Remove both the stoppers from locking bar assembly.

(v) Lock slides of the locking bar assembly are then inserted in to the groove of the stock

rail bracket (under the rail) through the guide of the lock arm. Fish tailed end of the

lock arm should be housed in the notch of the lock slide while inserting the lock slide

in the stock rail bracket.

(vi) The tongue rail brackets are then bolted to the web of the switch rail.

(vii) Fix the stopper of both locking bar assembly. Bend longer end of the lock washer on

the side of the stopper end on to the nut.

Figure 21: Inserting Lock slides into the groove

of the stock rail bracket (under the rail)

Figure 20: Fixing of Tongue rail brackets



(E) Connection of drive rod

(i) Connect drive rod lug to the

throw slide (Driving rack) of

point machine.

(ii) Connect the drive rod between

the drive rod lug and end of

locking bar assembly.

(iii)Adjusting screw of the drive rod

should be adjusted for 160 mm

opening of the switch.

(iv) Keeping the drive rod

perpendicular to track; fix the

point machine on the extended

sleepers on gauge tie plate.

Note: It is advisable to install the

point machine at the side where

the tongue is normally closed.

This shall be advantageous for

maintaining bars, which are then

inside the machine as much as possible.

(F) Connection of the Lock rods and Detector rods. (i) Lock and detector rods are to be

assembled at site by inserting drop lug

in the threaded portion of the rods. The

drop lugs can be suitably turned to suit

LH/RH mounting.

(ii) Put tapered washer on the foot

of the switch rail such that the thicker

portion of the washer is towards the

edge of the rail.

(iii) Now connect jaw of the

detector/lock rods with the foot of the

tongue rail and drop lug with the

detector/lock slide of the point

machine.

Figure 22: Connection of Drive rod

Figure 23: Connection of Lock & Detector rods



7.2 Installation as per RDSO drawing no. RDSO/S3454 ALT –A Ver.1.0

The procedure for IRS Point Machine with Clamp Lock and Ground Connection

arrangement 60 Kg (with Thick Web Switch) for B.G as per RDSO as per RDSO DRG. No.

RDSO/S3454 ALT-A Ver.1.0 is similar to that of RDSO DRG. No. RDSO/S3454, except

following (Refer Annexure III) :

(i). Provision of switch extension brackets (P brackets) for connecting Normal and Reverse

lock and detection rods with tongue rails, instead of direct connection to the foot of the

tongue rail.

(ii). Increase in Sleeper spacing 745 mm instead of 685 mm.

(A) Preparatory steps

Same as that given in Section 7.1 (A)

(B) Marking & drilling holes for Clamp Lock Assembly

Same as that given in Section 7.1 (B)

(C) Holes for Switch extension brackets (P brackets) to connect ground connections (Lock

and detector rods)

(i). For fixing of Switch extension brackets (P brackets) to tongue rails, two holes of 22 mm

dia at a height of 58 mm from the bottom of the tongue rail come prefabricated in the

tongue rail irrespective of LH or RH Tongue rail.

(ii) The first hole is at a distance of 40 mm from the edge of the tongue rail toe and second

hole is 295 mm from the edge of the tongue rail toe.

(iii) There is a gap of 245 mm between both holes (Centre-line to centre-line of the holes).

Figure 24: Holes on tongue rails for fixing of Switch extension brackets for ground

connections



8 Adjustment (a) Lubricate all the moving parts of the clamp lock assembly.

(b) Put grease on the bronze brush in the lock arm assembly.

(c) Put grease on the notches of the lock slide and fishtail portion of the lock arm.

(d) Loosen the nuts of stock rail bracket so that it can move freely in its oblong holes and

take its own portion.

(e) Operate the machine with crank handle and adjust the lock and detector slides (usually

Near end first)

(f) If clamp lock is not locking the point then do the following:

For proper locking on both sides additional numbers of packing shims have been

provided between switch rail and tongue rail bracket.

Required no of shims will be put outside the tongue rail bracket to facilitate locking on

either side.

Six numbers of packing shims are provided with each clamp point assembly.

(j) Now tighten the nuts of the stock rail bracket.

Figure 25: Position of notches on fish tail portion of lock arm for closed switch

Figure 26: Position of notches on fish tail portion of lock arm for closed switch



9 Testing

After installation the following test should be carried out.

9.1 Obstruction Test The detector slides, lock slides and drive rod must be so adjusted that with 5 mm thick test

piece placed between the switch and gauge face of stock rail at 150 mm from the toe of the

point:

(a) Friction clutch de-clutches the motor from mechanism.

(b) The point cannot get locked either by clamp lock or by locking segment inside the point

machine.

(c) Lock segment does not enter into the notches of locking slides.

(d) Switch detection contacts do not make.

(e) The slipping current is not exceeding twice the normal working current

9.2 Insulation Test Check the insulation for the following.

(a) Point machine Check that point machine is insulated from ground connection.

(b) Spring setting device Insulated from both the rails.

(c) Clamp lock assembly. Check that it is insulated from both the rails.

(d) Leading and following stretcher bar (If point is operated without clamp point

locking arrangement). They are insulated from both the rails.

Fig.1.16: Ground connections of point machine



10 Maintenance

Points

(a) Ensure graphiting or lubricating of slide chairs at every week.

(b) Ensure that all nuts and bolts are tight and split pins are opened properly.

(c) Lubricate at the following moving parts of the clamp lock fortnightly.

(d) Stock rail bracket groove.

(e) Moving part of tongue rail and lock arm assembly.

(f) Between machine of lock bar and lock arm assembly.

(g) Ensure that the rodding and other connections are tight.

(h) Check that the point area is well ballast, packed and free from vegetation.

(i) Check that water does not stagnate in the vicinity of points.

(j) Ensure information to engineering department regarding to avoid any emergency failure.

Point Machine

(a) Ensure that wire connections of the machine are tight and laced properly.

(b) Ensure that the locking segment enters freely into the notches on the lock slides and with

a little pressure in the notch of drive rod.

(c) Ensure the point machine fittings are tight.

(d) Check all parts for any crack or breakage etc. and replace immediately if any defect is

found.

(e) Ensure smooth working of the gears without any cracking noise.

(f) The slipping of friction clutch during obstruction shall be ensured and slipping current

shall not exceed twice the normal working current.

(g) Ensure that the carbon brushes are exerting sufficient pressure on commutator. Clean the

commutator properly by using chamoise leather.

(h) Ensure that all moving parts are free from dust and are well lubricated.

(i) Ensure that gauge tie plate is properly insulated.

(j) Ensure that the roller rolls freely on the periphery of the control and lift out disc.

(k) Check that the contact pressure of control and detection contact is adequate.

(l) Apply non-corrosive all temperature grease (IS-507/508) through the entire grease nipple

by a grease gun, after 8,000 operations or six months whichever is earlier or as per

instructions issued by the railway.

(m) After every six months or as per instructions issued by the railway pour lubricating oil,

SAE-30/SHELL 100, through inlet in to the oil reservoir for lubricating gearbox of the

motor.

(n) Check the overload current.



Track Locking schedule

Check track locking once in six months or as per instructions issued by the railway.

Workshop overhauling schedule

After 4,00,000 operations or five years for bigger yard or seven years whichever is earlier.

The point machine should be taken out and should receive a general overhaul and thorough

cleaning in an authorized workshop.

Insulation Testing schedule

Check insulation once in six months or as per instructions issued by the railway.

11 Troubleshooting Sr.

No

Nature of Failure Cause Remedy

1 Tongue rail not housing up

to 13 sleepers or tongue rail

housing one side properly

but not housing another side

at adequate distance.

Spring setting device not

adjusted properly

Arrange P-Way staff for

proper adjustment of

spring setting device.

2 Clamp lock not locking point

on either side.

Packing shims between stock

rail and tongue rail bracket or

outside the tongue rail are to

be adjusted.

Adjust the numbers of

packing shims of tongue

rail bracket.

3 Point machine does not start. Fuse blown Off. Replace the same.

Feed is not coming out from

relay room.

Check the circuit and

rectified

Cable conductor becomes

faulty

Megger the conductor,

replace if faulty.

Motor winding got low

insulation.

Replace the motor

While starting control

contacts are not making.

Adjust the control

contact.

4 Point is showing gap and

motor rotates continuously

Obstruction in between stock

and tongue rail.

Remove the obstruction.

In friction due to improper

cleaning and oiling of points.

Clean and check oiling of

point.

Wrong adjustment of point

throw rod.

Adjust point throw rod.

Defects with P.Way fitting. Attend with P.Way

staff.

5 Point is properly set, but

motor continuously rotates.

Respective detection

contacts are not making (Point

may lock)

Adjust detection

contact.

Adjustment required in lock Adjust lock rod for proper



Sr.

No

Nature of Failure Cause Remedy

rod, if point is not locked. locking

The respective detection

terminal loose or broken in

point machine.

Attend respective

detection contact.

6 1st point is correctly set,

locked and detection contacts

are making, but feed not

extended to 2nd

point

machine.

Feed not coming to 2nd

point

machine due to

cable between the machine

defective.

Check cable

conductor between

point machine,

replace if defective

or low insulation.

Crank handle contact of 2nd

point machine not making.

Adjust crank handle

contact.

Respective terminal loose or

broken in 2nd

point machine.

Tighten terminal or

replace broken terminal.

7 While operating the points

the motor rotates in just

reverse direction.

Any wire interchanged. Check wiring and

Rectify.

In point junction box cable

interchanged.

Check wiring at

junction box and

rectified.

8 First point is correctly set,

locked and detection made

but the motor do not stop

even after starting of 2nd

point machine.

Short circuit faults in the

terminals in point junction

box.

Check wiring at junction

box and rectified the short

circuit faults.

9 Out of correspondence

between point and relay

group.

Cables interchanged in point

junction box.

Check and rectify

Wiring interchanged in crank

handle box terminal.

Check and rectify



12 Do’s & Don’ts

Do’s.

Get disconnection of point, before carrying out any work.

Always ensure schedule maintenance.

Test the working of friction clutch.

Do ensure that track locking, route locking, crank handle release locking are

effective.

Do test the correspondence of the points with indication at panel or cabin.

Always use proper lubricant. Wipe away excessive oil or grease.

Always use proper rating of fuse.

Dont’s.

Do not operate the point manually except through specific crank handle.

Forget to exercise safety checks initially, during and after disconnection.

Forget to carry necessary tools while attending the failure.

Leave any discrepancies noticed in the point machine.

Use too much lubricant.

Allow unsquared notches on slides.

13 Tools & Spares

Recommended Tools and measuring instruments

Following tools and measuring instruments should be kept in the duty room for installation

and maintenance of Electric point machine:

Spanner set

32 mm (11/4”) single end spanner

Adjustable pipe wrench

Screw driver

Hammer

Tommy bar

Measuring tape

Test gauge

Cutting pliers

Wire cutter

Insulation peeler

DC Ammeter with centre ‘0’ incase of Analog (0-30 Amp)

DC Voltmeter (0-250V)

Track shunt resistance. Grease Gun



Spares and Consumables

Following spares and consumables are necessary for maintenance and inspection.

SAE 30/SHELL 100 oil

Grease IS 507/508

Chamois leather

Cotton waste grade A

Carbon brush

Contact assembly

MS-pins and split pins

D-bracket and stretcher bar insulation material sets

Tools and accessories to be supplied with new point machines

The following set of tools in a suitable box shall be supplied along with every set of eight

point machines or less:

1. Hand operated square drive socket wrenches of 12.5 mm driving square (short type) as

per IS: 7381 for M8, M10, M12 & M18 threads. (One 250 mm long 12.5 mm square

extension bar as per IS: 7991 alongwith compatible Tee handle Square drive as per IS:

7975 suitable for above socket wrenches.

2. Open jaw wrenches (spanners) for M10, M12, M20, M24 & M33 threads as per IS:

2028.

3. Adjustable wrench.

4. Screw driver 300 mm long



14 Summary

(1) Throw of point machine

Throw of the point machine throw bar – 220 mm, which is distributed as follows:

(a) First 60 mm throw of Point machine

(i) Unlocking of Closed switch and

(ii) Open switch moves 60 mm towards its stock rail.

(b) Next 100 mm throw, both switches move

(i) Closed switch opens by 100 mm and

(ii) Open switch completes (60 mm+100 mm) =160 mm and it is now closed.

(c) Last 60 mm throw

(i) 100 mm Opened switch further movers to 60 mm = (100 mm+60 mm) =160 mm.

(ii) Locking of Closed switch by 60 mm.

(2) Main Parts of point machine (a) DC series split field Motor within built reduction gear unit.

(b) Transmission assembly.

(c) Throw rod, lock slides and detection slides.

(d) Detection and control contact switch Assembly.

(e) Cast iron Case with cover.

(f) Crank handle.

(3) Components of Clamp Lock (a) Locking bar (L.H.)

(b) Locking bar (R.H)

(c) Insulating plates

(d) Locking washers

(e) Locking arms

(f) Stopper

(g) Drive lug

(4) Operating data as per IRS: S 24/2002 - Amendment No. 1

Motor- DC series split field

Throw of point machine - 220 mm + 4 / -1

Time of operation (Max.) - 5.0 sec.

Current consumption - < 5.5 Amp.

Rated voltage - 110 VDC

Max. Throw – 450 Kg.

Slipping load - < 580 Kg.

Stalling load (Min.) - 1000 Kg.

.



5) Installation

(i) General

Toe of switch at 32 mm in advance of centre line of sleeper No.3.

Distance between sleeper No.3 and 4 to 745 mm. (From centre-line to centre-line)

Insulated gauge tie plate on sleeper No. 3.

Removal of all leading and following stretcher bars.

Provision of spring setting device at junction of rail head (JOH).

Gap of not less than 57 mm at junction of rail head (JOH) for every flange way

clearance

(ii) Holes for Clamp Lock Assembly

(a) Stock rail

Two holes of 22 mm dia on the web of both stock rails at the height of 76 mm from

bottom for fixing stock rail brackets.

1st hole at 450 mm from the edge of the tongue rail toe.

2nd

hole at 530 mm from the edge of the tongue rail toe.

Gap of 80 mm between both the holes.

(b) Tongue rail

Two holes of 22 mm dia on the web of both tongue rails at the height of 55 mm from

bottom for fixing switch rail brackets.

1st hole at 428 mm from the edge of the tongue rail toe.

2nd


Gap of 70 mm between both the holes.

(iii) Holes for ground connection

As per RDSO Drawing. No. RDSO/S-3454

(a) Point machine on LHS.

Two holes of 24 mm dia on the foot of both tongue rails for connecting lock rod and

detector rod.

LH Tongue rail - 1st hole at 148 mm from the edge of the tongue rail toe.

2nd


RH Tongue rail - 1st hole at 200 mm from the edge of the tongue rail toe.

2nd


(c) Point machine on RHS

Two holes of 24 mm dia on the foot of both tounge rails for connecting lock rod and

detector rod.

LH Tongue rail - 1st hole at 200 mm from the edge of the tongue rail toe.

2nd


RH Tongue rail - 1st hole at 148 mm from the edge of the tongue rail toe.

2nd




As per RDSO Drawing No. RDSO/S-3454 ALT–A Ver. 1

Two prefabricated holes of 24 mm dia on the web of both tongue rails at the height of 58 mm

from bottom for connecting lock rod and detector rod.

. 1st hole at 40 mm from the edge of the tongue rail toe.

2nd

hole at 285 mm from the edge of the tongue rail toe

Irrespective of RH or LH tongue rail



15 References

IRS Specification no. IRS: S 24/2002 - Amendment No. 1 for Electric Point Machine

Non-Trailable type

RDSO Drawings for Ground connections of Electric Point Machine 220 mm stroke with

Clamp Lock for Thick Web Switch (TWS) (Drg. No. RDSO/S-3454).

Modified RDSO Drawings for Ground connections of Electric Point Machine 220 mm

stroke with Clamp Lock for Thick Web Switch (TWS) (Drg. No. RDSO/S-3454 ALT–A

Ver. 1) (RDSO Signal Directorate Letter no. STS/E/PM 220 mm Vol-I, dated

07.11.2019).

Modified RDSO design for Spring Setting Device (SSD) of Thick Web Switch (Drg. No.

RDSO/T 6216 ALT-4) (HQ Office S&T NCR Letter

no.NCR/S&T/1031/Signal/RDSO(Misc)/Pt -5 dated 01.06.2020.

IRICEN Pune's publication on Turnout - Laying, Inspection. Maintenance September

2014.

Manual on IRS Electric Point Machine Non-Trailable 220 mm throw -M/s Vossloh

Cogifer Signalling India Pvt. Ltd., Bhilai (C.G.)



16 Annexure I : Modified RDSO design for Spring Setting Device (SSD) of

Thick Web Switch (Drg. No. RDSO/T 6216 ALT-4)

17 Annexure II : RDSO Drawings for Ground connections of Electric

Point Machine 220 mm stroke with Clamp Lock for Thick Web Switch

(TWS) (Drg. No. RDSO/S-3454)

18 Annexure III : Modified RDSO Drawings for Ground connections of

Electric Point Machine 220 mm stroke with Clamp Lock for Thick

Web Switch (TWS) (Drg. No. RDSO/S-3454 ALT–A Ver. 1)

ANNEXURE I

Modified RDSO design for Spring Setting Device (SSD)

of

Thick Web Switch

(Drg. No. RDSO/T-6216 ALT-4)

ANNEXURE II

RDSO Drawings for Ground connections of

Electric Point Machine 220 mm stroke with Clamp Lock

for Thick Web Switch (TWS)

(Drg. No. RDSO/S-3454)

ANNEXURE III

Modified RDSO Drawings for Ground connections of

Electric Point Machine 220 mm stroke with Clamp Lock

for Thick Web Switch (TWS)

(Drg. No. RDSO/S-3454 ALT–A Ver. 1)

Quality Policy

“We at RDSO Lucknow are committed to maintain and update transparent

standards of services to develop safe, modern and cost effective railway

technology complying with statutory and regulatory requirements, through

excellence in research, designs and standards by setting quality objectives,

commitment to satisfy applicable requirements and continual improvements of

the quality management system to cater to growing needs, demand and

expectations of passenger and freight traffic on the railways through periodic

review of quality management systems to achieve continual improvement and

customer appreciation. It is communicated and applied within the organization

and making it available to all the relevant interested parties.”

INDIAN RAILWAYS

Centre for Advanced Maintenance Technology Maharajpur, Gwalior (M.P.) Pin Code – 474 005

handbook on installation & maintenance practices of

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