The last coach is the dummy car, it borrows all the resources from the maim powercar infront. The cab is just there to do the normal functions like driving, horning etc...
So u make videos on srilankan railways?? I would suggest u to make a video on list of all diesel and electric locomotives including EMUs available there. It will be really informative.
I have made a video on that a few years ago, you can find in detailed videos about SL engines on my channel ru-vid.com/group/PLr29emMDimd7nUtmTbn94xBXCefijyZdR
