by The EGE
I figured out where I was getting it from. Quoting from F-line's post in another thread a few months back:
F-line to Dudley via Park wrote:MBTA3247 wrote:Are the old trolley tunnels at Broadway even capable of handling Red Line cars?All tunnels have been built to Red Line dimensions spec since 1912, and since Broadway upper was built on the footprint of the underlying heavy rail tunnel it matches the dimensions.