MBTA Commuter Rail

The MBTA Commuter Rail (reporting markMBTX) system serves as the commuter rail arm of the Massachusetts Bay Transportation Authority's (MBTA's) transportation coverage of Greater Boston in the United States. Trains run over 429 mi (690 km) of track on 12 lines to 143 stations. It is operated under contract by Keolis.

In 2025, the system had a ridership of 29,707,200, or about 104,000 per weekday as of the first quarter of 2026, making it the fifth-busiest commuter rail system in the U.S., behind the three New York-area systems and the Chicago-area system. The lines' characteristic purple-trimmed coaches operate as far south as North Kingstown, Rhode Island, and as far north as Newburyport and as far west as Fitchburg, both in Massachusetts.

Trains originate at two major terminals in Boston – South Station and North Station. The only connection between the two halves of the system is the non-revenue Grand Junction Branch. The North–South Rail Link is a proposed tunnel between North Station and South Station to allow through-running service. Passengers currently connect between the stations using MBTA subway service.