YDM-4 Diesel Locomotive Internals

by Apurva Bahadur

There are some interesting points to note about the YDM-4 in the photograph below.

A YDM-4 loco just arrived in Mysore one morning... Photo by Apurva Bahadur, 2002.

The yellow stain near the radiator tank filler cap on the roof - this is from the coolant that contains yellow chromate additives for preventing corrosion.
Offset exhaust of the YDM-4.
Two of the six cylinders of the prime mover.
The radiator fan that is still turning.
Two cylinders of the four-cylinder expressor seen through the doors on the right.
The doors contain the primary air filter elements for the prime mover's air requirement.
The main oil bath maze filter is the large rectangular item on the top of the expressor.
DC motor and pump for lifting fuel from the tank - this is the greenish - blue cylindrical item on the loco frame - which has to run whenever the loco is live.
The curved item above the pump is the guard for the V-belts that drive the rear truck traction motor (RTTM) blower - the FTTM blower is driven off the bull gear on the free end of the traction dynamo/alternator.
Finally, note the lovely angled roof line of the YDM-4 loco!

YDM-4 locomotive specifications and notes