If you buy a cross-station Z257 train, but only buy a ticket from Yiwu to yingtan, but not a ticket from yingtan to Chongqing, then if you can't get a ticket on the train, you may be asked to get off. This is because you haven't bought a ticket from yingtan to Chongqing, so you can't continue to travel by train.

When making up the ticket, the conductor will check your ticket and travel itinerary. If you don't have a ticket to your destination, you may be asked to get off. In addition, if you can't make up the ticket, you may need to wait for the next bus at the station or the next station so that you can buy a ticket to your destination.

I suggest that you confirm your itinerary and seats when buying tickets to avoid this situation. If you need to make up the ticket on the train, you can consult the conductor or station in advance to understand the process and possible situation of making up the ticket.