Synchronised drives help give a train a lift during maintenance

21st February 2013

Katie Williams reports on one of most powerful lifting systems in the world which has been has been installed at a train maintenance plant.

One of the most powerful lifting systems in the world has been installed by the SNCF at its new East European Technicentre. A synchronised lifting line can lift a complete TGV train-set - some 200 metres long and weighing 386 tonnes - in just 10 minutes to an accuracy of a millimetre, thus allowing maintenance of the running gear.

This represents a world record in terms of the accuracy/volume/weight ratio and was achieved with the use of ac drives from Control Techniques in conjunction with asynchronous brake-motors from sister company Leroy-Somer, which was responsible for leading the project.

The new Technicentre, located on the outskirts of Paris, is the maintenance headquarters for the TGV Est, which links Paris to 21 cities in eastern France as well as 11 other destinations in Germany, Luxembourg and Switzerland. Journey times have been drastically reduced - Paris Strasbourg, for example, is reduced from four hours to just two hours 20 minutes.

There are a total of 26 jacking stands fitted along the maintenance line, each fitted with an 11kW AC drive, incorporating three plug-in modules to give additional on-board programming, Interbus networking capability and a universal encoder module for position feedback from the jacks. The asynchronous brake-motors were provided with remote absolute encoders for accurate positioning and fitted with brakes for security.

Over the full length of the maintenance line, positioning accuracy is better than 1mm. Set-up is quick and flexible. The operator can use all 26 jacks or fewer if the train is shorter and are interconnected by quick-release connectors. Communication between drives and the overall line controller is by Interbus-S.

Because of the high-efficiency and reduced turn-around times of the new maintenance facility, SNCF is assured of maximum availability of the 52 new train-sets, each representing state-of-the-art railway engineering capable of reaching a commercial speed of 320kph and requiring nearly 100 preventative maintenance inspections per year.

Recently a specially prepared TGV train-set achieved a world speed record of 574.8kph (357.2mph) near Le Chemin on TGV Est.

Meanwhile, the 2nd edition of the Drives and Controls Handbook, edited by Professor Bill Drury of Control Techniques, has just been launched.

The handbook, commissioned by the Institution of Engineering and Technology, gives a state-of-the-art insight into the technology and techniques of ac and dc motor control, from basic theory through to practical solutions.

This book replaces the edition published in 2001 and according to Professor Drury: "Very little of the last edition has made it into the new one without at least some modification and there has also been a lot of entirely new subject material included." This comprehensive and highly practical work runs over 750pages, retails at £80 and is available from Amazon, the IET and all good book retailers; however you can get 20 per cent off when buying it through the IET by visiting

The handbook draws upon Control Techniques' extensive engineering expertise in this field and encompasses all aspects of variable speed control, including AC/DC industrial motors, servo control, communications and system design.

Recognising that the handbook is used in a significant number of Universities as well as by industrial users, Professor Drury has added new sections covering basic electromagnetic and motor theory. New developments in areas including power semiconductors, functional safety and control have also been included.

A detailed consideration is given to the ambient conditions which influence the specification of a drive and associated equipment through to the characteristic impacts of drives. Guidance on EMC, harmonics, thermal management, cabling and fusing have all been significantly updated, including changes to international regulations.

The applications section has also been expanded, though given the breadth of this publication, it has been recognised that only core technologies and exemplars of use could be included.

The structure of the Handbook has been radically redesigned into four parts to make it easier to access:

- Part A: drive types and core technology.

- Part B: the drive in its environment.

- Part C: practical applications.

- Part D: Appendices.

Finally, a small, but important point is the revision of the index to make it easier to find information in the Handbook.

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Katie Williams is with Control Techniques Emerson Industrial Automation, Newtown, Powys, Wales.

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