High Speed Grinding High Performance Milling Flexis System

Rails perfectly maintained

Grinding, milling and switch maintenance

The right strategy for every track

Without maintenance, rails have to be replaced far too frequently at great expense and with considerable effort. If maintenance is only performed irregularly, rail defects continue to worsen until milling becomes the only remedy. Conventional rail grinding is only effective if carried out

very slowly, i.e. when the track is closed, and is inadequate in most cases. High Speed Grinding, on the other hand, achieves the best results in terms of rail quality, route availability and life cycle costs.

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Squats

Corrugations and slip waves

Advanced rail defects

Breakouts

Dam

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dept

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Wear limit / service life

Time / load tons

Conventional rail grinding

Prevention using HSG

Damage progression without maintenance

Milling

Head checks

High Speed Grinding (HSG)pages 4–9

Milling and High Performance Milling (HPM)pages 10–13

Flexis System for perfect switch maintenancepages 14–15

Illustration of strategies to combat rail wear and its impact on service life

The type of defect and its severity in the rail decide the strategy. Vossloh‘s experts develop a tailor-made maintenance strategy based on a track‘s individual characteristics using methods such as High Speed Grinding (HSG), milling and switch maintenance. While preventive grinding is particularly suitable for keeping near new and well-maintained tracks in good condition and correcting minor damage at the same time, rail milling strives to correct existing defects found deeper in the rail.Switches require special care; and here Vossloh has developed its holistic Flexis System.

It’s like brushing your teeth: regular care prevents wear and damage.Preventive rail maintenance using High Speed Grinding (HSG) applies this principle to rails, preventing rolling contact damage and corrugation and ensuring long-lasting quality and low costs.Regular grinding with the HSG-2 grinding vehicle and HSG-city can verifiably double the rail’s service life! Thanks to HSG, grinder burn as fertile ground for rail defects is no longer possible. And what‘s more: the procedure is also recommended as an effective and affordable noise reduction measure. High Speed Grinding is suitable for all railway systems from high-speed routes to city railway networks. Deployment can be flexibly adapted to the train timetable and all without closing or preparing the track!

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Regular grinding prevents damage!

HIGH SPeeD GRInDInG

ADVAnTAGeS

• Rails ground without track closures• HSG-2 reaches speeds of up to 80 km/h• HSG-city reaches operating speeds of up to 60 km/h• Longer rail service life• Significant noise reduction• No need to disassemble points and signaling equipment• Minimal sparks or dust• Completely suitable for tunnels• No overheating or gouging• Optimum grinding results without grooves• No restrictions at level crossings or sound absorbers• Transverse profile is optimized• Smoothing of the rail’s longitudinal profile

100 % longer

Deutsche Bahn, the Technical University of Berlin and others confirm: HSG doubles the rail‘s service life!

Here‘s how High Speed Grinding worksHeavy traffic and high speeds lead to cracks (head checks) and other damage like squats in the wheel-rail contact zone. HSG remedies this problem. Its patented grinding technology comprises special abrasive wheels arranged at certain angles and turned passively by the vehicle‘s propulsion. These rotate as they pass over the rails and

completely remove the damaged top layer.Three passes with the HSG train will remove a minimum of 0.1 mm of rail steel*, which reduces corrugation and slip waves and optimizes the longitudinal profile. The rail is “smoothed” while the dual dust extraction system captures almost all the grinding dust and sparks. *

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-2 g

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Prevents rail defectsReduces noiseBrings down costs

High Speed Grinding (HSG)

TESTED AND ENDORSED

DB Netz AG has compared two high-speed lines. The result: HSG is sustainably effective!

Technical University in Berlin: ”In comparison with conventional methods, regular pre-ventive grinding of the work-hardened rail surface reduces the life cycle costs of the heavily trafficked high-speed lines to 50 % and suburban routes to 61% respectively.“

Source: DB Netz AG 2013, Oliver Kraft

HSG-city (left) HSG-2 grinding train (below)

Set at an angle to the rail, the grinding wheels are pressed down hydraulically and grind very evenly

High-speed rail line between nuremberg and Ingolstadt (Preventive work since commissioning)

Expected service life of rails: 15–20 years

Technical service life

Commissioned in 2006

Pronounced head check growth due to express traffic

Corrective rail machining:Removal: 0.1mm 3 times a year (High Speed Grinding)Costs: 1 Euro per meter (3 Euros per meter and year)Head checks preventedEnd of service life and wear limit not expected to be reached before 2020

Max

imum

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High-speed rail line between Cologne and Frank-furt (no preventive work since commissioning)

Expected service life of rails: 8–12 years

Technical service life

Commissioned in 2002

Pronounced head check growth due to express traffic

Corrective rail machining:Removal: 1.8mm every two yearsCosts: 12 Euros per meter (6 Euros per meter and year)Head checks not completely removedService life ended by head checks and wear limit reached from 2010 on

Max

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HSG-2: fast, thorough and inexpensiveWith the HSG-2 High Speed Grinding train, Vossloh makes it possible for network operators to carry out rail maintenance within the timetable. This technology selectively removes only the work-hardened rail surface, thus preventing the formation of head checks and corrugation. The grinding pattern can be variably adjusted to optimize the rail‘s transverse profile as well – and all this at an operating speed of up to 80 km an hour! The extraction technology collects the material removed and its dust bunkers have an impressive six-ton capacity. Work progress is precisely monitored and the results are documented. Thanks to its modular design, two HSG grinding trains can be coupled together into a high-performance twin version.

SUCCESS KNOWS NO BOUNDS

HSG has been used in Germany since 2007, and also in Sweden, Denmark, the Netherlands, Switzerland and China. Here are some of the routes.

• Shanghai – Beijing • Cologne – Frankfurt• Nuremberg – Erfurt – Halle – Leipzig• Hamburg – Hanover• Amsterdam – Rotterdam – Brussels• Stockholm Airport – Stockholm• Berlin – Hanover• Mainz – Worms• Nuremberg – Munich• Copenhagen suburban railway

SUCCESS KNOWS NO BOUNDS

HSG-city is currently being used by many operators, e.g. the Rheinbahn in Dusseldorf, on the suburban railway system in Bremen, Beijing Metro and the Copenhagen Metro.

HSG-2 AND HSG-CiTy

TECHNiCAL SPECiFiCATiONS

• 96 grinding wheels• Operating speed: 60–80 km/h• Non-operational traveling speed up to 120 km/h• Shift output: up to 100 km• Rail roughness: Ra < 10 µm• Process parameter documentation• Reduces corrugation and slip waves• Optimizes rail‘s longitudinal profile• Recommended for machining noise-sensitive areas

Grinding train HSG-2

Grinding in heavy rail format – at high speed

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HSG-city was designed for suburban commuter networks, short main line routes, railway stations and special locations. At its heart is a grinding unit similar to the one used in the HSG-2: proven technology in a new dimension! With the HSG-city, Vossloh has the fastest grinding machine for metropolitan rail and short main line routes currently on the market. The maximum operating speed of 60 km per hour allows a workflow without track closures, so the HSG-city can be inserted directly into the railway operator’s timetable.HSG-city can operate pushed and pulled, so it can be used with many different kinds of traction machines, e.g. road/rail vehicles.

TECHNiCAL SPECiFiCATiONS

• Grinding wheels: 24• Operating speed: 15–60 km/h• Nonstop grinding capacity: 30 km• Rail roughness: Ra < 10 µm• Process parameter documentation• Controlled remotely from the traction vehicle• Required traction: minimum 170 kW, pulled or pushed• Twin version: two machines can be coupled together

HSG-city grinding machine

Short routes in sync with the timetable

km/h

Conventional grinding machines

HSG-2 and HSG-city

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Saves time and money and reduces noise

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1. Preventive grinding

3. Grinding to remove slippery build-up

2. New rail grinding

Regular preventive grinding runs remove the rail‘s work-hardened and brittle surface. Not only does this prevent head checks from forming, it also removes corrugation and slip waves and considerably delays the need for repair work and rail replacements.

High Speed Grinding is also effective in removing slippery films caused by the build-up of fallen leaves or air pollution. The resulting good grip when braking and accelerating serves to increase safety.

Grinding new rails removes manufacturing-related defects of the rail and evens out the rail‘s transverse profile. New rail grinding (mill-scale grinding) is the initial machining of the rail in the factory or in the track bed after manu- facturing or milling. This grinding delays the onset of rail damage. Machining is done either in the factory or in the track bed depending on the lengths used and the track-laying conditions. Machining the rails once they have been laid does have advantages, however, because any damage inflicted on site can be rectified and removed.

NEW RAiL MACHiNiNG

• Removes the decarbonized layer/mill scale• Creates a uniform and continuous rail head profile• Extends the machining intervals because the formation of defects is delayed• Eliminates alignment errors in site-welds

HIGH SPeeD GRInDInG

Rails before, during and after HSG machining

4. Acoustic grindingThe wheels rolling on the rails are a major source of rail noise. Optimizing the wheel-rail contact using High Speed Grinding minimizes corrugation and slip waves and reduces the acoustically relevant roughness of the rail. Consequently, traffic using the “smoother“ rail generates significantly less rail noise. Various measurements have shown that HSG grinding demonstrably results in an acoustic improvement of up to 10 decibels.

All the data gained from previous experience, e.g. with the Rheinbahn in Düsseldorf, indicate that preventive rail maintenance leads to audibly quieter rail traffic. HSG technology has also been designated by DB Netz AG as the official method for noise reduction, also for „Besonders überwachtes Gleis“ (BüG), (tracks specially monitored in noise-sensitive areas).

• Smooth wheel (K, LL, disc brakes)

• Smooth rail (ground using HSG, no corrugation)

• Smooth wheel (K, LL, disc brakes)

• Rough rail (aggressively ground rail, corrugation forming)

+10 dB(A)*

iT‘S NOT “WHiSPER-QUiET“ WiTHOUT QUiET RAiLS

Grinding is an essential part of rail maintenance, but aggressive grinding reduces the effectiveness of the high-quality “whisper brakes“ considerably and leads to long-term damage. HSG grinding protects both wheel and rail and mitigates noise by up to 10 dB(A)*.

* Data from the sonRAIL project results, Thron

Aggressively ground rail with facets and heat damage

HSG grinding pattern immediately after grinding

Here‘s when HSG is used

Replacing grinding wheels

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High Speed Grinding

Rail milling restores the rail to its original profile. The rail is given a new surface and thus the best possible basis for a long-term maintenance strategy. Milling optimizes the rail to the specifications in the relevant directives andreprofiles it using the following parameters.• Defect depth• Rail profile• Rail inclination• Track gaugeAfter the milling process, the ideal scenario would be to switch to a preventive maintenance strategy (best case: High Speed Grinding). 

High material removal rate to counter defects deep in the rail Reprofiling to the original condition ADVAnTAGeS

• Minimizes costs over the long term• Optimizes the rail‘s operational availability• Postpones difficult and costly rail replacement works• Extends the rail‘s service life and impacts extremely positively on rail life cycle costs

MiLLiNG

RANGE OF APPLiCATiONS

• Track correction• Machining heavy-rail routes for high-speed passenger traffic, freight and mixed use• Removing longitudinal and transverse rail head defects• Reducing rolling noise and wear • Altering rail profiles• Re-profiling

The milling principle: remove deep defects in a single pass

As it machines the rail head, the milling

wheel completely re-profiles the rail

Running edge

RE-LAyiNG USED RAiLS

There are still places where, if rails are worn out on the running edge, they are taken up, rotated and re-laid – a laborious process after which the only recourse is to replace the rails entirely. This procedure also involves the risk of existing defects continuing to worsen. Milling, on the other hand, will restore the rail surface and post-pone the necessity of rail replace-ment much more effectively.

Milling reaches far deeper into the rail than grinding and removes rail defects that are already well advanced. As a consequence, rail milling is primarily used in applications where conventional grinding is uneconomical. It cansignificantly delay the costly necessity of removing and replacing rails andextend a rail‘s life cycle considerably.High removal rate: Rail milling is a cutting process that removes deep flaws in a single pass. It is precisely controlled to within one tenth of a millimeter and capable of removing up to 3 mm of metal.

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Here‘s how rails regain their profiles

Rail Milling

Def

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Time

MiLLiNG

The future of rail milling

High Performance Milling (HPM)

Corrugations, deformations and fatigue damage: In order to avoid the necessity of expensive rail replacement, Vossloh has further refined its existing milling technology:We call the result High Performance Milling (HPM). This method rectifies defects precisely and accurately re-profiles the rail, removing up to 3 mm of metal from the running surface and up to 10 mm from the running edge in a single pass! In the post-machining phase, instead of grinding Vossloh uses modern face-milling technology which produces no grinding dust, making HPM the cleanest rail machining procedure in the world.A tool calibration system ensures the work is of consistent quality, and the rails are subsequently checked by integrated measuring technology that takes longitudinal wave, transverse and, if required, eddy-current measurements. Once machined using HPM, the rail profile easily fulfils the requirements of the Deutsche Bahn Directive No. 824. Work in tunnels or inner city areas requires no extensive clean-up afterwards, and the diesel-electric drive also provides maximum energy efficiency. High Performance Milling is adaptable to all common international profiles and can be used for local and heavy-traffic routes.

Deeper, faster and more precise

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Milling is kind to resources and the environment and regarded as the cleanest rail processing method available. In today‘s standard process, the rail head is re-profiled very precisely using peripheral milling in combination with peripheral grinding for the finish. Incorporating two milling units and a grinding unit coupled together, it is a procedure that functions according to the principle of “mill, mill and grind fine“.Vossloh milling trains can be used with most standard-gauge and private rail- ways. Level crossings are machined along with the rest of the route and prior dismantling of signaling equipment or other systems is not required.The trains traverse the track routes at an average speed of 13 m/min. The maximum machining depth is about 2 mm on the contact surface and 5 mm on the running edge.After the milling process, the rails are checked for defects and machining quality by integrated and/or external measurement devices. The result is a dimensionally accurate restoration of the rail profile with a guaranteed transverse profile accurate to +/- 0.3 mm* and a longitudinal profile accurate to 0.02 mm. The quality of the surface roughness is Ra < 10 µm.

The right solution for every task ENViRONMENTALLy FRiENDLy

• No grinding dust• No sparks, no fire hazard• All the metal chips are extracted• Completely suitable for use in tunnels• Can also be used in sensitive areas• Dry machining without water• Reduced noise through optimized wheel-rail contact

ReFeRenCeS

Besides the German core market, Vossloh also mills internationally in many other european railway markets (Switzerland, the Nether-lands, Sweden and Denmark, among others).

environmentally friendly and flexible

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Rail MillingWE TURN A BiG WHEEL

At the heart of the HPM machine is the milling wheel. With a diameter of 1400 mm, this high-performance milling wheel achieves the previously un- attainable non-stop milling speed of up to 2 km/h.

Standard HPM

Conventional

Vossloh

Reduced residual waviness due to larger milling wheel diameter

ADVAnTAGeS

• Our milling wheel is now twice the size• Dust-free finishing technology as post-machining process• Modular: 1–2 milling units and 1 finishing unit. Milling module, drive module, chip bunker module, work shop module etc. mounted on container wagons and connected according to the plug-and-play principle• Higher operating speed• Machined rails given the highest surface quality• Exact restoration of rail profile in a single pass• More material removal per operation• integrated finishing technology• The rail‘s service life is increased• Maximum fire safety thanks to spark-free operation• Very environmentally friendly• Reduces rail noise

FLExiS

The Flexis System: optimal prevention and switch maintenanceWith its Flexis System, Vossloh is implementing its holistic approach to switch maintenance. As fundamental elements of a railway network, switches are exposed to high loads. Wear and tear can produce defects such as skid spots, head checks and corrugations which can result in switches having to be replaced prematurely.Periodic preventive measures considerably reduce the switch‘s susceptibility to breakdowns. With Flexis, the switch is checked regularly, preventively ground and any damage discovered is always repaired while still in its early stage. This ensures operational safety, keeps costs down and extends the switch‘s service life many times over. And what‘s more: the minimal rail roughness and the restored rail profile combine to reduce noise emissions.

Flexis: systematic care

Switch Maintenance

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Coordinated package of measuresRemoving mill scale after installation is the ideal start to switch maintenance. In addition to removing defects, Flexis also has preventive switch grinding as one of its central components, ensuring that all parts of the switch that come into contact with train wheels remain in top condition. The switches are machined in several passes by our Flexis team, who use machines designed and further developed by Vossloh which can be on-railed and off-railed quickly. Track possessions as brief as 10 minutes are already sufficient.Our strategy is based on recording and documenting the condition of the switch. Vossloh uses various tools for this purpose including DQM to record the transverse profile, RM 1200 digital to determine the longitudinal profile, RHM for measuring the loss in rail height, and a WPG eddy current tester to detect the depth and spread of rail damage. The eddy current test determines the location and depthof defects while rail geometry measurements are taken in order to aid the process.

THE BENEFiTS OF A SySTEM

• Fast on-railing and off-railing• Can also be performed during short track possessions• No removal of track switching equipment required• Switch machined completely, including tongues and frog• Eddy current testing according to DB requirements• Optional adaptation of system to the scope of work required• Frog re-profiling• Reconditioning welding carried out if required• System is DB-approved for all routes

THE FLExiS SySTEM

• Machines for transverse and longitudinal profile machining

• Material removal exactly according to identified requirements

• Machining work can be docu-mented in writing or digitally

• Performance example: new rail with a 300-meter radius machined in approx. 4 hours

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Find out about our other rail maintenance services:

Vossloh Rail Services GmbH · Hannoversche Straße 10 21079 Hamburg · Germany · Tel. +49 40 430931-0info.lifecyclesolutions@vossloh.com · www.vossloh.com

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