What do metro trains do when they reach the end of the line?

[LeCycliste]

I have always wondered this because I've rode some of the lines all the way to the end. When it gets to the end, the operator will make an announcement something like "this train is going out of service". They do this, but then some people will stay on the train.

My guess is the train loops around and head back the other direction on the line...so is there a loop at the end of each line?

Thanks for any clarification!

[scirocco]

The majority of metro line and trains don't have loops, in France or anywhere else (there is the odd exception). Trains have a driving cab at each end so that it can be driven "backwards" without having to turn round.

But usually the train will not be driven backwards on the same line - they will keep to the left or the right hand line when facing the direction of travel, depending on what country they are in. So that means that the train has to cross over to the other line. That involves driving a few hundred metres to a set of crossover points (switches) before coming back on the other line. This maneouvre is not part of the regular passenger service and passengers are not really supposed to be on board, which is why you get the "train going out of service" announcement.

Alternatively the train may genuinely be going out of service for some time before the next trip, and they don't want people to be inconvenienced by sitting on a train that isn't going anywhere for a long time.