MRVC Rake Tests

In July 2007, the Mumbai Rail Vikas Corporation (MRVC) was preparing to induct several new rakes into use on the Mumbai suburban system. These rakes were built by Siemens. As part of acceptance trials for the new rakes, the following tests were run over a period of 32 days, starting from late July after the first of the new rakes was to arrive (July 25). All tests were run at night between 1am and 4am to minimize interference with normal commuter traffic. Tests were run on both CR and WR tracks.

Test 1: Signal & Telecom; 2 nights

In this test, the rake is run between Churchgate and Virar twice each way ways to ensure that the train's signalling system can work on the newly deployed audio frequency system. The testing occurs over 9, 12 and 15 coach formations.

Test 2: Oscillation trials; 12 nights

This test measures the jerks and oscillations that result in the rakes in response to normal rail curvature, level changes, rail profile variations, bumps and other irregularities. A maximum of 3 G's of acceleration is considered tolerable. The testing is done at a variety of speeds, up to 110km/h.

Test 3: Braking distance; 12 nights

In this test, dummy loads are used in the coaches to increase the load being hauled, and brake efficacy is tested in terms of the stopping distance from various speeds. The dummy loads, called 'brake loads' weigh about 13kg each. As an example, to test braking distances for a load of 500 passengers, assuming 60kg for each passenger, brake loads totalling up to 30t are placed in the coaches.

Test 4: Parking brakes; all 32 nights

This test is carried out on a rake with 15 coaches left parked in various locations at different yards with tracks that are level and also with slight inclines, and exposed to possible vibrations from nearby lines. The object of the test is to ensure the rakes do not under any circumstances roll back on to running lines from where they are parked.

Test 5: Dynamometer tests; 6 nights

This test measures the brake horsepower available from the traction motors as well as the retarding power of the brakes under different circumstances, and when operated simultaneously.

Test 6: Auxiliary subsystems; all 32 nights

These are tests of subsystems such as the passenger information system, fire detection and retarding mechanisms, lighting, ventilation, etc.