The Boston Elevated Railway designed its own version of a double truck lightweight car and bought a total of 471 from 1922 to 1928. The Type 5 semiconvertible has the Boston front and the inward taper from window sills to roof, but in most other details it resembles other cars of this period. No. 5734, built by Brill in 1924, and No. 5821, also a Brill 1924 product, are both owned by the museum. While basically identical, they differ slightly in that No. 5821, acquired in 1954, has narrower front window frames and posts, forming what was termed a "vision front".