For the unaware, the entirety of FO:NV development could be considered "crunch time" because the studio, Obsidian, got royally screwed on the contract to make the game instead of the main Bethesda studio(s).
The result is that the game originally had some plan for vehicles, most of which never made it past concept, but never got implemented. So, in order to make a moving Tram to ride into vegas from the south, if you somehow manage to complete an obscure and somewhat buggy sidequest to stop it from getting blown up, they just made the Tram an NPC which physically runs along the track. It works surprisingly well.
