I did the research: The MBTA spends 7.5% of its budget on 0.5% of its trips (The Ride).
I also have another agency that the MBTA is paying for, but shouldn't:
Transit Police. It should/could easily be part of the State Police Department.
EDIT: Interestingly enough, the MBTA spends over $100M on The Ride, close to the amount of its operating deficit.
Transit Police is more complicated than that. Most large transit agencies have a police department, and most large private railroads have a police department (yes, even CSX and Pan Am have guys with badges and guns who can legally arrest you). State Police don't have the training to safely patrol some of the more dangerous transit infrastructure. Different story on a bus-only system, but if a suspect makes a getaway down the Red Line tunnel to slip out at one of the emergency exits you need the officers who have the training on doing a footchase on crossties 2 feet from a live third rail and has recall of every hiding place. Or know the layout of a yard when they're hopping between tracks doing a routine security pass around the sprawling South Station terminal district. An in-house PD just becomes a more necessary practicality the bigger the scale of the system. Most definitely if you have an established PD it's not wise to consider abolishing it or slashing it too far back, because State and Local PD's just don't end up filling the void because of the onerous safety training. NYC Subway has not fared well at all during past budget swings when they've let the MTA PD ranks atrophy with retirements in an attempt to save money. The T is a very, very safe system compared to NYC, Chicago, Philly, SF, etc. and any troubling upticks in crime tend to get stamped out pronto. It's one of the good things we've got going for us, so there should be great reluctance to mess with that.
Now, if they are too bloated in ranks (and we'd need to see some hard figures and comparisons with other systems to determine) there may be some shaving they can do on the bus side. But I really don't think you're talking more than pocket change because most bus depots and routes are spot patrols and any bus locations large enough to require semi-constant Transit Police tend to be at conjoined rapid transit stations.
The Ride...yes, that one I think has no business being entirely under their purview. It's too large a paratransit district to cover in-house, and there are enough private and municipal carriers providing same or similar general service that an outsource program subscribed to a common fare structure and interoperability clauses if one carrier has to cross districts to drop off a passenger would help a lot on the efficiency front. Paratransit is a very common loss leader for transit agencies; the T is hardly an outlier in being saddled with it. They tend to be legacy operations absorbed from similar private carriers as when the public agency cobbled together its bus district from formerly private carriers, and then the ADA's passage cemented it in place. But after 25 years of the ADA enough private paratransit service has infilled the auxiliary demand that the same circumstances that led the transit agencies to take on the task in the first place from lack of other options...no longer exist. Especially in an urban core, and especially where a whole ecosystem of private shuttle and personal transit operators have sprung up around the universities and medical centers.
That one just needs to have lawmakers craft up some legislation setting up a common fare program and creating the licensing rules and standards for Ride-spec service divvied up across the district...with no loss of cross-district mobility. It's not hard to do, but it's action only the Legislature can initiate. And, you know, "Reform Before Revenue" hasn't exactly gotten any show of hands in either chamber of volunteers willing to take the first crack at crafting a reform...any reform.
