Know About Locomotive WDM7
(Class name carried over from old system.) Fifteen of these locos were built from June 1987 through 1989. A few were at Erode earlier but later all were transferred to Ernakulam. More recently [8/02-11/02] several (#11003/06/07/08/09/13) have been seen being used as shunters at Chennai Central or for light passenger haulage. Some are now in Golden Rock livery while others are still in Ernakulam livery. A few may [11/02] still be at Ernakulam, but it appears that all are destined to be moved to Chennai or Golden Rock to work odd jobs.
These Co-Co diesel-electrics were designed for branch-line duties (top speed 105km/h). They have bodies with two 3-axle bogies and are similar to the WDM-2 in appearance. The power-pack is a 12-cylinder Alco 251B unit. They are now used mostly for shunting, and occcasional branch-line duties on the Trivandrum – Kottayam, Cochin – Alleppey, and Cochin – Trivandrum sections. The first 10 have generators and a top speed of 105km/h. The last 5 in this series have dynamic brakes, alternators, and a top speed of 100km/h. Both batches have a 94:17 gear ratio.
Engine: Alco 251B-12 variant, 2000hp
Transmission: Electric, with BHEL TG 10931 AZ generator — DC shunt wound (first 10), or BHEL TA 10105 AZ alternators — 3 phase star (the last 5)
Gear ratio: 94:17
Fuel capacity: 5000l