Batteries for Stockholm Transport Commuter Trains
01 December 2005 10:40
Alstom has selected fully integrated battery systems, based on Saft MATRICS (Mass Transit Rail Integrated Compact battery System) MRX rechargeable nickel-cadmium batteries for the 55-strong fleet of Coradia Lirex EMU commuter trains now entering service for Stockholm Transport (SL). Two battery systems, each comprising two 110V, 230Ah capacity batteries, are mounted in the roof of each six-car train to provide up to two hours of reliable back-up power for safety and auxiliary circuits
The Coradia Lirex trains, built by Alstom in Salzgitter, Germany, have been designed to suit the unique conditions of Stockholm commuter traffic. SL's requirements included fast acceleration levels (stations are close to one another), numerous wide doors, a low floor for increased accessibility, and the capability to function safely and reliably in extremely variable weather conditions.
All the traction equipment, as well as heating and ventilation systems and the onboard batteries, is roof-mounted. This configuration makes more passenger space available as well as allowing for a continuous low floor. It is also well suited to rigorous Swedish winters as it reduces the ingress of snow, and makes the equipment easily accessible for maintenance. Reliability is a vital factor for all the train systems as headways (gaps between trains) in the centre of Stockholm are less than ten minutes at peak times, so any failures could prove extremely disruptive to services.
Saft has helped Alstom to utilise the weight and space saving capability of the MATRICS MRX batteries to maximum effect by developing a bespoke battery system to make the best use of the available roof-space. This included taking complete responsibility for the design, manufacture and supply of a stainless steel battery box, fully vibration and shock tested to the appropriate rail standards. The box houses 78 MRX 230 cells in series, divided between two compartments, complete with connectors, on/off switch, isolators, a contactor, fuses, temperature sensor and centralised filling system.
MATRICS MRX BACKGROUND
The Saft MATRICS MRX battery was developed in response to customers seeking smaller, lighter battery packages optimised for maximum performance and reliability, reduced maintenance and low life cycle cost. It provides the low maintenance and long service life benefits of sintered / pbe technology within a slim, lightweight block battery package, housed in a flame retardant polypropylene case, which has a major size and volume advantage compared with conventional batteries.
For train operators, the MATRICS MRX integrated water filling system is important. This simple to use feature fills all the cells from one central point and substantially reduces the battery's maintenance requirements by enabling cells to be topped-up quickly, safely and accurately, maximising the battery's useful life.
Saft MATRICS MRX batteries are available in blocks of three to ten cells, running in parallel or series, with rated capacities from 70Ah up to 260Ah. For customers wishing to further enhance the compact size and weight advantages of MATRICS MRX batteries, Saft is able to supply fully integrated, turn-key battery systems in bespoke trays or battery boxes.
For more information on this company:
Saft - Nickel-Cadmium Batteries for Mass Transit Applications
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