Well is a map in the Team Fortress franchise.
In Team Fortress 2, there are three official versions of it: a CP, or control point, version, a CTF, or capture the intelligence, version and an Arena version. The CP verison was released with the game, while the CTF version was released after release through automatic updates for the PC version of Team Fortress 2. The Arena version of the map was released alongside the Heavy Update.
Trains will periodically drive through the middle of the map, killing players they hit. Even players made invulnerable by an übercharge. The CP and Arena versions of Well have a big building in the middle with two sets of train tracks. The CTF version of Well lacks the central building and only has one set of train tracks.