This is no surprise. NGC locos are very common at Ambala. You will always find one or two there. This is a freight loco, so it is very unlikely it comes in with a passenger train. By the way all NGC locos are ACD fitted.

no surprises to find NFR loco at Ambala. Could have brought Gauhati-Jammu Tawi exp! But why was it delinked at Ambala and not carried uptill JAT?

First snap in IRFCA of a NFR BG loco. Seems it is ACD fitted too. Maybe the only shed in the north to have ACD fitted locos. Any more?

Abu Road

Jimmy, a long time back, Erode shed had this type of livery especially for the Brindavan, pre Electrification days, just a memory

This loco had an AC cab for a long time. Seems it still has. The cab door is closed and there is a blackened box near the horns, which must be the AC

The rear loco obviously looks like a LKO WDM-2 due to it's blue/grey livery and the front one seems to be from Katni shed. Just a guess!

cool design looks like a loco in North America

Please note there is no difference between a "WDG-3A", WDG-2 (Old nominclature) and a SHAKTI. Shakti is just a name provided along with change in livery

Quite so. It is evident in the next pic.