I was talking with TransitMatter's regional rail director earlier today, and asked him how he'd solve the Braintree chokepoint on the old colony lines.
He suggested ripping out red entirely and converting the whole thing to a two-plus 1 express track regional rail corridor. This seems like a bad solution at first, but with the new room we can talk seriously about SCR via Old Colony, and if we run that plus the other three lines we're talking ten minute headways.
Yes it's a very radical change, but could it work?
No, it would not work and it's a horrendously bad idea. It would worsen headways to Dorchester and Quincy, because they can't be dispatched as tightly out of an open-network terminal like South Station with interdependencies on every other train in/out of SS. RER is very, very good frequencies but it is
NOT the same as thing as a closed-system heavy-rail subway that only has to dispatch itself between Alewife and Columbia Jct. to meet an aggressive frequency target. And those Red frequencies to the branches are set to get a lot better with the new cars, signal renewal, and dwell-taming practices anyway so the gap is set to widen in 3 years.
I can't believe a TM flak would be whispering about robbing someone's frequencies to either pay for someone else's or uphold one's own integrity-of-concept. Talk about loose lips sink ships...that is lethal for coalition-building. This better not become a habit of them.
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SCR via the Old Colony is utter swill anyway with worse travel times, worse frequencies, and transit loss to boot (Cape rail, Middleboro station) compared to the only half-broken Stoughton Alternative. It'll never work as useful transit, and they've got threatened lawsuits from (so far) Towns of Middleboro and Taunton to stop it dead if it proceeds any further than the enriching-consultants PowerPoints stage it's in now. I firmly believe that because of the threatened lawsuits it's still Stoughton-or-bust, though they have to challenge the Army Corp's faulty DEIR on the single-track swamp trestle and factor in some serious NEC upgrades if they want to un-break the artificial capacity pinch.
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There are only 3 OC branches, and flights-of-fancy about SCR aside there's only going to be 3 OC branches. You can run 3 branches of RER on 2 tracks; the Eastern Route is going to do exactly that without need to add tracks if Peabody/128 comes online, so nothing's unprecedented here. And the OC's not going to get bogged down on 2 tracks because the 3 inside-128 stops are all majority exit-only transfers to Red and buses with very low dwell times. Something the TM flak should've been aware of before proposing to go against the grain.
Also, density on the 3 branches has to be factored in. You can run near-"Indigo" 15-20 minute all-day frequencies to Brockton because it's the largest city en route and has a very large bus terminal. But...
- Middleboro/Buzzards Bay isn't going to fetch crumbs at 15-20 min. levels because those are a semi-rural to rural bedroom communities comprising very spread-out geographic area. This is typical "495-land", more appropriate for 30+ min. turns. Service throttling at Brockton is going to be necessary.
- Cape Cod is so detached from Greater Boston, with stagnant long-term population growth and transit demand that's so dependent on bridge traffic by time of day that it probably can't justify more than hourly service with maybe a slight peak surge. Probably another service throttle looming at Buzzards Bay before crossing the bridge.
- The Plymouth Line intermediates likewise lose their quasi-"Indigo" demand south of Weymouth, and go semi-rural south of Whitman (though Abington & Whitman can be boosted on all-day demand if they joined the BAT bus district full-time). Plymouth is a decent-size city...but also physically large and very spread out, and well-detached from Greater Boston. Some service densification with the northern half of the line (possibly with infill stops) is plausible, but it's not nearly as clear-cut as the "Indigo-Brockton" example. Everywhere else is pretty clearly "495-land".
- Greenbush's only dense region in Weymouth is well within reach of the Quincy Center bus routes, then the density falls way off around Hingham as the rest of the corridor becomes bedroom communities. Not sure there's even a clear dividing line for a mid-line service throttle here, so might as well all be considered a single "495-land" schedule.
Keep in mind that RER practices don't mean a flat hyper-dense headway everywhere to everywhere on a large, sprawling system. Under no circumstances do those practices ask the operator to bleed itself dry running the same homogenous service levels to places of heterogeneous demand. That's an essential difference from the flat headways on rapid transit & branches.
So it's fully OK if the Old Colony only has full-on "Indigo"-branded 15-20 min. headways to Brockton at the single largest multimodal and density demand catchment, but everywhere else gets grouped in with the 30+ minute schedules. It's not at all incongruous if service levels to the exurbs get throttled down, because that's what we'll be doing anyway for 128 vs. 495 terminating runs. And not incongrous if Hyannis has to throttle down some more for being very far-detached from Boston, because that's what we'll be doing for interstate destinations equally far like Wickford Jct. Middleboro/Cape isn't even an outlier at having multiple throttles, because if you consider Haverhill/Reading as 1 line instead of 2 separate ones it'll have the same number of throttles: Reading for "128/Indigo" frequencies, Haverhill for "495-land" frequencies, and Dover, NH for regional intercity frequencies.
What makes it all still RER-practice is that:
- ...the schedules are clock-facing at the given headway so riders do not have to be shackled to the paper schedule to plan trips.
- ...the schedules enhance transfer utility with last-mile transit like feeder buses (also prioritizes clock-facing).
- ...the given headway is run bi-directionally to keep equipment efficiently in rotation instead of bottled up in layover yards as happens with peak-direction schedules.
- ...if peak augmentation is needed, those slots should try to fit in between the clock-facing headway and disrupt it as little as possible.
It's not as complicated--or compromising--as it sounds. There's a general understanding with RER that "inside-128" is going to have more frequent service than "128-to-495" is going to have more frequent service than "intrastate intercity/across state lines". Simply because that's the broad-based way demand is organized across the system. And that's completely consistent with how the OC would get sliced/diced.
