Wellington station has two island platforms between the three Orange Line tracks.
The western platform serves both inbound (southbound) and outbound trains, while the eastern platform is used only for outbound trains.
It was intended for use by express trains using the third track; however, the planned extension to Reading was cut back to Oak Grove and no express trains were ever run.
The fare mezzanine is located over the north end of the station.
The busway and parking lot are located on the east side of the station.

Wellington Yard, the primary maintenance and storage facility for the Orange Line fleet, is located west of the station.
A parking garage shared by the station and the Station Landing development is west of the yard.
It is connected to the fare mezzanine with a 800-foot (240 m)-long enclosed walkway.
Wellington station is fully accessible from both entrances, with elevators connecting the mezzanine to the platforms.

A footbridge at the south end of the station connects only to the maintenance facility and is not in public use.
The MBTA plans to rebuild it as a public entrance, with a footbridge to the east parking lot.
A design contract was awarded in April 2020.
Wellington station has two island platforms between the three Orange Line tracks. The western platform serves both inbound (southbound) and outbound trains, while the eastern platform is used only for outbound trains. It was intended for use by express trains using the third track; however, the planned extension to Reading was cut back to Oak Grove and no express trains were ever run. The fare mezzanine is located over the north end of the station. The busway and parking lot are located on the east side of the station.
Wellington Yard, the primary maintenance and storage facility for the Orange Line fleet, is located west of the station. A parking garage shared by the station and the Station Landing development is west of the yard. It is connected to the fare mezzanine with a 800-foot (240 m)-long enclosed walkway. Wellington station is fully accessible from both entrances, with elevators connecting the mezzanine to the platforms.
A footbridge at the south end of the station connects only to the maintenance facility and is not in public use. The MBTA plans to rebuild it as a public entrance, with a footbridge to the east parking lot. A design contract was awarded in April 2020.
Wellington station (MBTA)