Title - CR to alter DC rake design for faster commute

Commuters can soon get to travel on faster and punctual suburban trains if the Central Railway is able to run Direct Current (DC) compatible rakes at 100 kmph as against the existing speed limit of 80 kmph.
    CR will undertake trials, and if successful, the travel time for a 60km journey can be reduced by at least 8 to 10 minutes.
    The traction between CST and Kalyan operates on 1500 V DC technology. Beyond Kalyan, it has switched to 25 KV Alternating Current (AC). Hence, CR runs both, DC technology rakes and AC-DC dual technology rakes. CR general manager Subodh Jain told TOI, “At present, it is not possible for AC-DC rakes to hit 100 kmph because of the presence of slow-moving DC rakes on the same path. Once all rakes in the system have a uniform speed limit, it will be possible to run faster trains.”
    CR aims to improve punctuality of services. Jain explained, “If speed of all trains improve, a local will have time to catch up with the loss in time due to any failure.”
    CR will have to make technical changes in the DC rake’s design to make them run at 100 kmph. DC rakes are not allowed to cross 80 kmph because its coaches have air-springs, which are likely to break if the compartment has dense crush load and the train exceeds the speed limit. When this happens, the train stops. Jain said, “We will replace air-springs with airbags that are provided in the Siemens manufactured purplewhite AC-DC rakes that already run at 100 kmph on Western Railway. Air-bags are less prone to failure. Even if they burst, the train will still ply at 65 kmph.”
    Trials are likely to be conducted in presence of the Research Design and Standards Organisation on January 15. Jain said, “Oscillation trials will be conducted, which includes vertical and lateral movement of trains at 110 kmph. The ride index would also be measured to ascertain the comfort level.”
    After trial, a speed certificate is issued and a joint safety certificate has to be given to confirm that the track, the coach and OHE network can handle trains of this speed. An application will then be sent to commissioner of railway safety for relaxing the speed limit.
PUSH FOR PUNCTUALITY
Total no of rakes | 119 DC rakes | 57 Speed limit of DC rakes |
80 kmph
Speed limit of AC-DC rakes |
100 kmph Time saved | 8-10 mins for 60 km journey Total cost of project |
    2.4 cr per rake Trials planned on Jan 15 Services may start around
Feb 15, 2013