Originally Posted by
ceejay
One place where you must carry the actual passport is on a train. The railways have their own police force and they have, I believe, a policy of always arresting if you are caught without it. This is on the grounds that, if you are on a train then your passport is not readily available as it would be if it was in a condo or hotel room 10 minutes across town.
I have had my passport checked on a long distance train. The sleepers often have 1 or 2 railway police on them and, on a 12-14 hour journey, it gives them something to do.