What electric loco lease? Nobody has enough spares to spare for covering the whole of the Providence schedule. Because it has to be the whole schedule to strip out the schedule padding predicated on an 'any' schedule. You get no improvement if we lease a couple Sprinters from Amtrak but every nth trip is pot luck for an F40.So if we have the 93 mph capable coaches with the 2022 order, does it make sense to lease an electric push/pull locomotive rather than EMUs? Given our recent investment in rolling stock, it would seem that we will be running push/pull for some time, especially outside the 128 zone.
Tightening's going to happen in stages. FIRST you get the new coaches online, ban the slow single-levels from Providence/Stoughton, gerrymander the locos to all-HSP/no-F40...and bank those gains into a refactored all-day schedule. Then you adopt EMU's...put up with 2 years of slow factory acceptances where there's still too many diesels out there...but do it conforming to the bestest/93 MPH diesel schedule so the transitional waste isn't so absurd. Then when the all-electric numbers are critical mass, lower the boom: diesels shadow-banned as a rule, whole new schedule refactoring shedding all that padding and more dramatic gains.
Skip steps or half-ass it and you end up getting the worst of all worlds: expensive new toys running an unchanged schedule padded to absurdity because lowest-common denominator equipment may still be taking the occasional 'any'-turn. You have to actually raise that denominator in discrete steps to get the advantages. Watch Caltrain completely and utterly miss this point with their all-too-piecemeal electrification...and see how unimproved their Baby Bullet schedules are on those unicorn-modded Stadler EMU's when they mix in traffic with gimp F40-hauled strings of gallery cars running to the un-electrified-maybe-forever Gilroy end of the line.
Even when you're talking the installment plan, the individual installments have to be whole-hogged to net those time-saving schedule revisions that shed the extra padding flab.