Union Railway Car Barn

The Union Railway Car Barn is an historic building in Cambridge, Massachusetts. It is a large brick $2 1/2$-story building, with a distinctive round-arch central window and a stepped brick cornice. Its ground floor has been converted to a retail storefront. It was built in 1869 to house the horse-drawn streetcars of the Union Railway Company, founded in 1855. It is the only surviving car barn of three built by the company in Cambridge, and a rare surviving element of the city's 19th-century transportation infrastructure.

The building was listed on the National Register of Historic Places in 1982.