There was another, the Boston, Revere Beach & Lynn. This 3 foot gauge line used semaphores until electrified in the late 1920s. You can make a reasonable facsimile of these signals by taking Sirgibby's Murchison 2 semaphores and setting them on the right side of the track. After electrification, the line used a mix of two and three light signals. The stock US 3 light signals look about right for it. The line was abandoned in 1940.
EDIT: Yes, it remained 3 foot gauge when electrified. During steam ops, it used single Fairlies.... er, Mason Bogies, exclusively.
Cheers,
Ben