Which Train and Class to get From Mumbai?

I have been on the trains several times, and there is virtually just one class: Sleeper class. Unless you are referring to First Class.
You may want to consider First Class; in June, the temperature will be hot and First Class has A.C. (Sleeper class has fans.)

Dear wheelrim,

Unless otherwise,most trains have:

1)Second A.C.(2 tier A.C.): It has 2 bunks on each wall.Which means that both passenger can sit on the lower berth during the day and during the night both have their own berth to stretch themselves.

2)3 Tier A.c : Instead of 2 berths there are 3 berths.The middle berth(which is the backrest for the lower berth ) is raised during the night when it is the time to sleep.During the day only the lower berth is occupied by the 3 passengers.If you wish to interact,learn about India,offer snacks & food etc. then in this arrangement one gets the opportunity to share the space and talk to the other passenger.I suggest that you may take this option as it provides for conditioned cool air at lower cost.

3)Sleeper class(2nd class): One saves money but is not well appointed and has no A.C.

I like the way you ask the questions.It is pleasure answering you.
Best wishes,
Art
P.S. The railway has announcements requesting passengers to not accept food,snack or beverages from strangers/other passenger as it could be laced with intoxicants ultimately resulting in robbery or theft. Horror stories, anyone?

Thanks for that. Cheers