From Team Fortress Wiki
Ha ha! Look at you! You look like you ran through traffic!
— The Scout
A Train is an environmental hazard which first appeared in the map Well, and has been used in other maps since. Trains typically appear on the map in the form of a railway crossing complete with warning lights and a ringing bell sound effect. The speed and the timing of the Train's appearance varies by map.
Contact with the front of a Train results in the destruction of buildings and death of the player, including players currently receiving an ÜberCharge from a Medic. Players who cause an opponent to be struck and killed by a train through knock back or wound the player by any other means before the death will not be credited with a kill assist. The Dead Ringer will provide protection from the initial impact of the train; further impacts will lead to death.
- Stickybombs launched at a moving Train will be stuck in the air at the point where the Stickybomb and Train met, instead of moving along with the Train.
- The Train's design resembles that of the EMD GP38-2, a model of locomotive first introduced in the 1970s.
- The Train bears the company name "Northern Express". Sharing its paint scheme as well, this is likely a nod at real-life American railroad, Southern Pacific. The GP38 used to operate in Southern's fleet as well.
- The damage type of the Train is coded in the Source Engine as freezing.
- The train's number of '7331' is the popular gaming phrase 1337 ('leet' in numbers, a text version of the word 'elite') backwards.