Believe it or not, I've got an HO-scale MBTA F40PH from LIFE-LIKE!
I do also have an MBTA horizon coach car and cab car from Walthers, and they work fine. I mean, sure they don't look like MBTA's REAL current F40PHs...
(This is what most of the real MBTA commuter trains I see in my area have.)
...but it still looks pretty realistic IMHO. You could even get this Life-Like Snap-Loc commuter station building kit, and with a bit of customization and kitbashing have it look like a more authentic MBTA station: