Last night, to amuse myself, I timed how long it took between platforms on a few segments of the Providence line, and then measured the distance on Google maps:
Route 128--Canton: 4 mins, 3.3 miles
Canton to Sharon: 3 mins/55 secs, 3.2 miles
Sharon to Mansfield: 6.5 mins, 6.7 miles
S. Attleboro to PVD: 9 mins/15 secs, 6.5 miles
So... 49 mph, 49 mph, 62 mph, 42 mph. Overall the trip is still 70 minutes by train to do what is a 48-mile drive on I-95. Still really not that competitive to a car-based commute in terms of time and expense (with the massive caveats that the train, as a passive experience, is zero stress and relaxing and a decent work environment if necessary).
But, will this EMU accelerate those legs at least by a mere 20%? (60 mph, 60 mph, 75 mph, 50 mph) to make it competitive with driving (at least time-wise... expense, that's a tough calculation perhaps).
If not, given the minimum 10-year wait... why bother, if the speed gain is going to be so marginal?
It's a little more nuanced than that.
Right now, the HSP-46 locomotives and Kawasaki/Rotem bi-level coaches are maintenance-rated for 93 MPH max authorized speed. But the F40PH-3C/GP40MC/MP36PH-3C locos and all single-level coaches are only rated for 79 MPH. If
one single member from the 79 MPH ranks is assigned to a Providence consist the whole consist gets kneecapped to a 79 MPH max limit...even if all other members of that same consist are rated for 93. Right now there just isn't enough 93 MPH equipment to gerrymander to Providence schedules without risk of at least one single-level coach or one slow locomotive turning up in the rotation...and of course you would have to gerrymander across the
whole day's schedule to see any net improvement. The coaches are the cause of this. It wouldn't be too difficult to segregate loco assignments because the HSP's are slightly north of 50% on the southside ranks, but right now there's just far too many single-levels out there on the southside to play any plausible game of keep-away against random-chance. Because of South Station's current capacity choke swapping set assignments isn't as easy as it should be, so playing the artful gerrymander with Providence/Stoughton is an order of magnitude harder than it should be.
Also...the HSP's are a much brawnier 4600 HP with lots more pep out of a dead stop than the other 3 classes of older 3000 HP locos. The performance disparity is
greatest on lines that have the longest rush-hour consist configurations, like Providence, because the 3000 HP engines can struggle mightily to pull 8 full cars out of a stop. This imposes its own inefficiencies on the schedule, as there is lots of padding between stops to cover the acceleration disparity. The HSP's, taking off faster, tend to burn up a lot of their advantage margin with schedule-keeping coasting while the day's schedule is overall predicated on the 3000 HP gimps taking any turn in the rotation even during peak-most rush-hour. It's a born inefficiency on the Providence schedule they would love to not have to live with...but something's got to give because playing the keep-away game with both locos and coaches is too collectively difficult.
All of this changes soon.
The +80 Rotem coach order for 2022 displaces all of the remaining single-level cab cars (north and south), while retiring the last of the duct-taped MBB trailers and 1 of 3 order batches of Bombardier trailers. With that shift in numbers you
will have enough bi-levels to gerrymander Providence assignments to all- 93 MPH-rated sets, because they'll easily be at/past the two-thirds mark in total southside fleet makeup by then. And in turn the (somewhat easier) gerrymander of HSP-46 locos to Providence/Stoughton without needing to worry as much about coach rotations means that you get the brawniest-accelerating 4600 HP diesels running the route full-time, with the other gimpier 3000 HP locos able to be de facto segregated off the (non-Needham) NEC. That will necessitate a wholesale schedule refactoring, as all of the padding allotted for the lower speed limit gets stripped out along with all of the padding for the 4600 HP vs. 3000 HP acceleration disparity. Because those two types of performance padding loom so large over the Providence schedule, you may see something close to that 20% between-stop savings being enacted
before the first electric vehicle trawls the line. And you may see some actual (if very brief) >80 MPH cruising speeds between stops with the uniform-rated equipment, as well as for-real 90 MPH on segments of express trains. That's coming in as little as 3 years on the same diesel trains as the coach roster flushes itself with replacements.
Your EMU performance gains are then
on top of that bolts-tightened faster diesel schedule. So the travel time gains do indeed project dramatic enough to lop 10+ minutes off the trip for the same number of stops in the end. Because this is not just one rung of on-vehicle performance enhancement...it's two. And all of the most egregious schedule-padding fat gets stripped out way before the electrics arrive.
Yes...it'll absolutely be time-competitive with a 48-mile drive on I-95 when all is said and done. But present-day schedules already bury a very large lede on performance crippling because fleets are just not elastic enough to segregate. The electrics will be tuning a schedule that's already lost its most wasteful padding beforehand.
