This is the first level in Portal Stories: Mel. It starts in a tram ride, introducing Cave Johnson, C.E.O. of Aperture Science; and someone named Chris, who is fired soon afterwards for misspelling the word 'station'.
During the beginning train ride, it’s possible to see a security guard knocking on a door, which is a reference to a similar event in Half Life: Blue Shift.
The character of Chris and his firing is a reference to how level designer Chris Onorati accidentally misspelled "station" as "statoion" on a sign, which started a running joke of the team "firing" him whenever he made a mistake.
Map: st_a1_tramride.bsp