Saft’s MSX batteries take a high profile role on New York City’s Aerial Tramway renovation project

Saft has developed the MSX series nickel-based rechargeable batteries to deliver safe and reliable backup for safety critical onboard systems in the rail industry. Two batteries have been installed on each of the two new tramway cabins to provide the sole source of power for the door opening and locking systems, as well as internal lighting, WIFI communications and ventilation. The compact lightweight design of the MSX offers a 30 percent weight saving, compared with a conventional nickel-based battery, enabling the cabin to carry more passengers. “The key aims of the Aerial Tramway renovation project were to increase the reliability of the service for passengers, maximize safety and improve energy efficiency, and making the correct choice of onboard battery was crucial in achieving these aims”, says Stéphane Alléon, SEMER project leader. “Saft’s MSX battery enabled us to meet all our design requirements in terms of performance and high cycling capability as well as offering a very significant reduction in weight and installation footprint.”

The MSX batteries are in service for 20-hour shifts – from 06.00 am to 02.00 am – during which time each cabin makes 185 round trips over a 945 metre journey between Manhattan Station and Roosevelt Island at a height of 76 metres above the East River. The 24 V, 100 Ah batteries discharge during the 170 second single journey to power the electrical systems. They then connect automatically to a docking station at the loading quay to recharge. The recharging time available varies from 120 to 420 seconds, according to the frequency of service which reflects both passenger numbers and the time of day. In addition to the normal service, the batteries are also required to provide emergency backup for up to three hours should a cabin be halted between the two stops. This type of high cycling application is particularly demanding on the onboard batteries. A further challenge is presented by the extreme temperatures encountered in New York City, ranging from -5°C to +30°C. MSX batteries offered the ideal solution for SEMER as they have been developed specifically to deliver high power capability and high cycling performance over a very wide range of temperatures, from -20°C to +40°C. Furthermore, the MSX design incorporates an integral centralized water filling system that makes maintenance fast and easy, helping to meet the operator’s requirement for minimal maintenance. Each battery features 18 MSX 100 cells