Eurostar what is the procedure is it like a train?

Question

do they check your passport and that

Answer 1

Yes, it's a train.

And yes, they check your passport since you are crossing an international boundary.

Answer 2

It is a high-speed train that goes from London (St Pancras International) to Paris and Brussels via the Channel Tunnel. Be prepared for passport checks on the European side outbound and the British side inbound.