As per wikipedia
This train belong to SER, but this website says it is belong to ECOR.
Find the below paragraph copied from wikipedia
This Train Belongs To South Eastern Railway and Coaches are Maintained at Santragachi Coaching Depot Of South Eastern Railway. This train is Hauled By an Santragachi (SRC) WAP-4 From Howrah Junction to Igatpuri, and from Igatpuri to Mumbai...
more... CST, it's Hauled By a Kalyan (KYN) WCAM-3, Because Of Direct Current (DC) Traction Ahead From Kalyan.