The Type 10 LRV is a future class of low-floor light rail vehicles, to be manufactured by Construcciones y Auxiliar de Ferrocarriles (CAF) for the MBTA Green Line in Greater Boston, Massachusetts.

A segment of the E Branch on Huntington Avenue still uses street running in mixed traffic, and the system's storage facilities are direct descendants of historic car barns.

Terminal stations and storage facilities feature small balloon loops for turning around trains, which constrain the physical dimensions of Green Line cars.

During the Green Line Extension construction, the Lechmere Viaduct was reinforced to carry heavier trains, removing a weight limit that served as a major bottleneck in the system.

[5]: 13 To operate service on the Green Line Extension, the MBTA ordered 24 Type 9 cars from the American branch of Spanish firm Construcciones y Auxiliar de Ferrocarriles.

[2]: 7 The MBTA considered 7 concepts for new Green Line cars in a 2018 study, taking into account future modifications to the system's sharp curves and weight restrictions.

The MBTA's final concept for the new cars was a 114-foot (35 m) articulated low-floor light rail vehicle made up of 7 segments, riding on 4 trucks, and equipped with 5 sliding doors on each side.

[5]: 30–35 To operate the concept light rail vehicles, the MBTA found that infrastructure modifications would be required at multiple locations in the Green Line system.

[11] The Green Line Train Protection System program has been delayed substantially after the MBTA fired an underperforming contractor in June 2024, and will enter service well after the previous estimate of 2025.

The full-scale, half-length model includes functioning bridge plates and mockups of passenger information systems, seating, and operator controls.