Does anyone actually use these terms other than in official notices and announcements? I used them in a thread recently, but they sound very old-fashioned and pompous, and I wonder how many passengers actually know what they mean. I suspect there may be some who think the signs saying "do not alight here" are saying they can't smoke a cigarette 
"Getting on" and "getting off" are probably a bit too informal, but why not just talk about "joining" and "leaving" the train?

"Getting on" and "getting off" are probably a bit too informal, but why not just talk about "joining" and "leaving" the train?