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Saft MRX rail batteries are playing a weight-saving role in the success of Bombardier’s ALP-45DP dual-powered locomotives, aimed at operators in the US.

By substituting traditional lead-acid batteries with Saft’s compact and lightweight nickel-based batteries, Bombardier’s design team has achieved a 60 per cent reduction in the weight of the onboard battery system, enabling the locomotives to meet critical axle weight limits.

The ALP-45DP locomotive features Bombardier’s Mitrac dual-power propulsion technology, which is particularly suitable for partially electrified tracks that require high levels of reliability, cost effectiveness, flexibility and respect for the environment.

It makes it possible for the commuter trains to operate in both electric mode with power from the catenary line and in diesel mode, providing a ‘one seat’ ride that improves passenger comfort and reduces journey times.

Due to this flexible drive technology, these locomotives can be used on the entire networks of the first purchasers, New Jersey Transit (NJT) and Canada’s Agence Metropolitaine de Transport (AMT) in Montreal.

The dual-powered locomotives require a 72V onboard battery system capable of meeting four widely varying load profiles.

The battery has two primary functions: to ensure the continuity of all vital electronic control circuits and other vehicle loads while traversing neutral sections of the overhead catenary where the AC power supply is interrupted; and to provide cranking power to start one of the two 1,567kW diesel engines.

The battery also has to provide backup support for all vehicle-control loads in the event of a failure of the battery chargers, as well as support for critical safety loads, such as emergency lighting and the train radio system, and also for layover periods when the vehicle is stationary with no external supply.

Previous Bombardier locomotives in the US have utilised standard lead-acid battery blocks designed for fleet use within NJT, but this was not feasible for the dual-powered locomotive, as the standard lead acid batteries weigh 1,100kg, while the Saft MRX batteries are only 425kg but provide equivalent performance.

In addition to the critical need to save weight, the Saft MRX batteries provide additional benefits for Bombardier in terms of optimised total cost of ownership due to the service life of at least 15 years in this application and ease of maintenance.

In particular, the integrated water-filling system enables the cells to be topped up in-situ within the battery compartment, minimising maintenance time and disruption compared with lead-acid cell blocks that would need lifting out of the compartment for servicing.

The battery system for the ALP-45DP locomotive comprises a total of 56 Saft MRX cells, with a nominal voltage of 72V and a capacity of 160Ah.

The first systems have been supplied by Saft in readiness for the dual-powered locomotives to commence track testing in early 2011.

Over the next two years, Saft will supply at total of 46 battery systems to Bombardier.

26 of these will be installed on New Jersey Transit locomotives in the US and 20 on AMT locomotives in Canada.

Saft Industrial Batteries

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