15028-WDP1M-BZA --- Photographed by Subhadyouti Bose. D.O.P. - 2nd March 2018.

Due to repeated issues regarding maintenance of bogies of WDP1, some modifications are done by RDSO to address those issues. Thus new variant of rebuilt WDP1 locomotives comes with rubber springs in the suspension in place of coil springs, higher capacity hydraulic dampers with changed location, softer helical coil springs in primary stage, wing type axle boxes and the axle load of WDP1M is 20t. Other designs & parameters are same as of WDP1. The oscillation trials in rajdhani tracks performed by CRS to establish the speed potential of WP1M locos yielded satisfactory results regarding riding quality & stability charecteristics on a tangent track, station yard & curve at a maximum speed of 135 kmph. Based on these satisfactory trial results these locos got speed certificate to run on 120 kmph at rajdhani tracks & 105 kmph at non-rajdhani tracks.