This sale is for 7mm scale model kit of a "Mannin Models" Darjeeling Himalayan Railway NDM-6 Diesel Loco. 
 
The kit consists of a body, separate roof and cab interior as well a seperate headlight gaurds so you can fit your own lamps if desired. 
 
It is wide enough between the frames to fit up to a 16.5mm gauge model
 
You will need paint, glue, chassis and couplers to complete.
 
https://www.locosnstuff.com make a specific chassis for this loco or you can source your own. 
 
Dimensions-
 
At its widest point- 48mm
118mm long
39mm wheel base
Inside width of frames 22mm