Should one encourage giving tips (bacshis) to the attendants and cleaners in AC and Sleeper coaches in super-fast trains like Durunto and Rajdhani in India?
Officially, you are not supposed to / expected to give tips to anyone on the Indian Railways network. On most express or mail trains, these attendants used to be IRCTC employees, a public sector company but many of them are now being directly handled by the Indian Railways while on other routes, these are handled by private companies.
Regardless of who employs them, I don't reckon the attendants get paid a lot for the long hours they work (most superfast train journeys in India are twelve hours or over in length), the number of people they have to deal with (hundreds, literally, on every train), the kind of environment they have to work in / sleep (just go to any catering coach) isn't particularly great.
Understand that things like quality of food served et al is often out of their hands as these are pre-cooked in large kitchens off the train and then loaded on at specific stations during the journey. (The exception is breakfast, which is usually cooked on-board.) Trying to hold them responsible for food is a pointless exercise as this is something out of their control but I've lost count of how many times on train journeys in India people act with a entitled attitude towards train employees, ordering them around like personal servants or being rude to them. At least the attendants on Rajdhani / Shatabdi / Duronto have it better.
Most of them do try to earn their tip by being nice to you. Still, when it comes to tipping it is customary to pay at least Rs 20 as a tip (more if you're a larger group or particularly like the service, I'm not sure how much this has changed in recent times due to inflation). Fractionally, it's an incredibly small cost to add to your journey but when pooled together it definitely goes towards making life easier for someone with a family who isn't well off and works long hours.