Well, it's trendy with NJ Transit doing it. And if anyone trawls the outer Fitchburg Line often enough to see Norfolk Southern intermodal trains run, NS has the most extensive series of
heritage loco paints in the industry honoring the innumerable defunct RR's that were absorbed (X many times removed) into their network, with those units on regular rotation on the Patriot Corridor. And their paint shop at famous Altoona Works RR shops is so good they're almost always spot-on accurate (because they'll hear about it from a rabid army of HO-scale foamers if a single line is non-authentic).
I'm just not sure what would quality as "T heritage". It's been variations on the same purple scheme with few radical changes ever since they first first equipment purchases in the late-70's. The Boston & Maine heritage on the northside is hard to replicate because the Budd RDC's were all- stainless steel with just logo decals, no "paint". Their only paint jobs--both the blue-dip paint w/ BM logo and the earlier
red w/yellow stripes and Minuteman logo were freight-only jobs, with the steam era basically being non-schemed dull colors that absorbed soot well.
Southside you've got the good old NYNH&H interlocking NH, but State of Connecticut already wears that as its home scheme. Most Boston & Albany trains ran in pool fleet with their corporate owners New York Central...sometimes stickered with the
cherry-red B&A logo over whatever the prevailing NYC scheme of the day was, but usually not. (pre- D Line Brookline Village, mid-1950's). . .
.
And, well...the less said about the
Penn Central era in Boston the better.