The Type 9 LRV is a class of low-floor light rail vehicles manufactured by Construcciones y Auxiliar de Ferrocarriles (CAF) for the MBTA Green Line.

The MBTA's light rail vehicle types follow the nomenclature of the Boston Elevated Railway, which operated five series of cars.

In response to the difficulties faced with the Type 8 fleet, the MBTA revised its procurement practices, focusing on project management by internal staff.

The MBTA also committed to providing equipment manufacturers with more precise specifications of its infrastructure, which is unique due to its age and condition.

In May 2014, CAF USA, the American subsidiary of Spanish firm Construcciones y Auxiliar de Ferrocarriles, was selected to construct the new LRVs.

[5] Buy America regulations meant that the bodyshells of the cars were manufactured in Spain, with final assembly at Elmira, New York.

They are the first light rail vehicles in the United States to incorporate crash energy management technology, a form of crumple zone that protects the train operator and passengers in a collision.

[13] Accessibility features include improved bridge plates for faster step-free boarding, and larger reserved areas for users of wheelchairs and strollers.

A misaligned floor panel in the center section of a Type 9 car buckled under load, requiring the train to be evacuated.