How are locos numbered in IR???
The locomotives that have codes such as WAP4E, WAP 6, WAP 7, etc are electric engines meant for passenger trains and similarly WAG locomotives are meant for goods train.
The locomotives having codes WDM3A, WDP4D are diesel engines used for both passenger as well as goods train.
Electric locomotives have a pantograph on top while the diesel locomotives don’t have.
I am attaching an image which will give you a clear idea of the designation of locomotive codes.