Saft Batteries Provide Emergency Power for Virgin Tilting Pendolinos
27 June 2005 15:54
Alstom Class 390 Pendolino EMU tilting trains, now in service with Virgin Trains on the West Coast Main Line, rely on Saft SRX batteries to provide the vital power supply support through overhead line neutral sections that ensures correct operation of their tilting mechanism as they travel at speeds of up to 200km/h.
By leaning into curves while maintaining full speed, the Pendolino tilting trains reduce travel times and provide greater passenger comfort without the need for specialised infrastructure. However, the electric actuators that tilt the trains require a considerable amount of power within a short period of time - typically a peak load of 20kW for around a second.
In addition to powering the tilting mechanism through overhead line neutral sections, the on-board battery is required to support the remainder of the train control system during this period. Furthermore, in the event of total power failure, it has to provide short term power support to the tilt mechanism, to maintain passenger comfort while the train speed is reduced, followed by a further 90mins back-up power for emergency lighting, communication and door opening systems.
Saft worked with Alstom to develop a fully integrated on-board rechargeable battery system capable of fitting into the available space under the floor of the train cars. Each battery comprises 72 Saft SRX 1200P cells, with a nominal capacity of 115Ah, supplied ready to fit in a battery box complete with connector. One battery is fitted to each of the nine cars of the 53 nine-car Pendolino train sets.
The SRX design features sintered positive and plastic-bonded negative electrodes which make it significantly smaller and lighter than conventional batteries of similar performance, an important consideration for modern rolling stock which places a key emphasis on low weight for maximum energy efficiency. In addition it is extremely reliable, it does not suffer the "sudden death" failure that can afflict lead acid batteries, and can provide a long service life of up to 15 years. This extended lifetime exceeds the minimum lifetime required by the UIC 854 R railway specification by more than six times.
A further advantage of the SRX for Virgin Trains is that the battery will need no special attention between normal rolling stock maintenance examinations. Topping up with distilled water is only required at two-year intervals, and there is no need to change the electrolyte during the battery's lifetime.
For more information on this company:
Saft - Nickel-Cadmium Batteries for Mass Transit Applications
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