Consultation on whether to reserve a sleeper on the train ticket halfway.

The berth ticket did not get on the bus from the station on the ticket, which may exist: the berth is sold to the hard seat to make up the berth!

It is not allowed according to the relevant regulations! However, out of self-interest or commission, it is not excluded that the train conductor will sell the ticket to other passengers privately. But you can get on the bus halfway and argue with the conductor with your ticket. Or just complain to him. Good luck! !