An alternative to tailgating; beers you enjoy on the commuter train when going to a sporting event.
My friends and I like to enjoy some train beers during the ride to the SF Giants game.
The consumption of alcoholic beverages, preferably beer, in the company of coworkers on a train ride home from work, usually on a Friday afternoon or evening.
Joe: What time is the beer train departing today?
Tom: Leaving work at 4. I'm gonna hit up the liquor store across from the station. Anything in particular you want to drink?