Re: Fairmont Line Upgrade
The Worcester Line is already double-tracked. Do you mean triple-tracked? That isn't required if you can cross over between the tracks. Nor is a whole set of Yawkey-like Death Star stations. They need high-level and disabled access to meet ADA requirements anyhow - they'll have to rebuild all those stations before 2024 as it is, but all they need is a high, preferably island platform with an elevator and stairway to the overpass above. Yawkey apparently had to be more elaborate because it sits on a curve, which only applies there.
Worcester Line can handle it fine if there are ample number of crossovers for longer-haul trains to pass the locals. Right now there are 0 passing opportunities whatsoever between the west end of Beacon Park and Wellesley Farms, so when an outbound is running wrong-rail to serve the single-platform Newton stops it means nothing can move inbound from Wellesley Farm until the outbound has served all 3 stops. Similar constriction exists if you double up the platforms but flush the headways so full a Worcester train gets caught up behind a Riverside DMU. On the other hand, Yawkey has a pretty dense concentration of nearby crossovers before the station and on both ends of Beacon Park so it doesn't introduce any strain to pack that one full of trains.
The way to fix that involves resignaling the entire line and installing frequent crossovers. Template the immediate Yawkey vicinity out to 128 and the Riverside turnout. Like, if there's a passing opportunity once every 2 stations from before Newton Corner to the Riverside turnout where the Worcesters can bob and weave around the DMU's those overtakings will fit snugly inside the densest headways for all these overlapping services without creating new conflicts. It's a lot of traffic engineering to design and plot out the meets over 10 or 20 years worth of traffic growth on each flavor of service (the DMU's, the Worcester locals making every past-128 stop, the Worcester super-expresses that skip most) and bullseye where the crossovers need to be installed, but the line absolutely has that kind of capacity to tap.
New Balance/whatever-they're-calling-it does have the slack space for a real passing track since it's on the footprint of the ex-Beacon Park yard leads. The Grand Junction dinky probably isn't going to intermix with the mainline at all after it converges until it's at the station proper. So that one does have bona fide express vs. locals separation potential. Either out-of-the-box or as a later reconfiguration. The Pike reshaping isn't pinching that space on the mainline easement.
The big DMU-specific station costs are new stations at Beacon Park and Newton Corner, as well as a fair amount of reconfiguration to allow the DMUs to make it to the existing platforms at Riverside. Most of their construction costs here are going to be Federally-mandated whether they add DMUs or not.
And don't forget doubling up the Newton platforms. Those won't be Yawkey-difficult on the track curvature, but some finessing around the retaining walls and bridge abutments, shifting platfoms a few dozen to couple hundred feet to avoid start of curves, and ADA egress placement will take some time, money, and design precision.
I actually don't think Needham has the demand profile for DMUs in its current commute-facing configuration. The Needham line has rapid transit level demand from the Needham stations north (toward Newton and the Needham St. corridor) and north from West Rox/Roslindale toward Downtown. As has been explored before, the T could and should break the line in half and replace the commuter rail with Green and Orange Line service on those two trajectories.
The problem is more that Needham's the perpetual odd-man out squeezed by NEC congestion and never is going to be able to buy enough headways to run at Indigo service levels. And a dinky that terminates at Forest Hills would get a storm of protest by making the service more expensive than the Rozzie/W. Rox buses to FH for no more convenience, and kill the Needham ridership dead. The only long-term solution is prying it off the CR network. Finessing any enhancement requires punishing someone else in zero-sum fashion. They're stuck in a very tough place when you look at all the facts and figures Amtrak and the T/RIDOT are circulating about projected NEC growth for 2020, 2030, 2040.
It's a shame that no rapid transit expansions made the 2024 plan, but even if DMU service is being tacked on as the T tries to suck up to HRT extension supporters (Lynn anyone?) a DMU-based service on the existing Needham Line makes no sense because DMUs in commuter rail settings are about trading capacity per train for frequency. Needham/Boston is a highly-peaked market with little all-day demand, so no go.
I very much disagree on the all-day demand thing in Needham. The projected Green Line ridership for a spur out of Newton is extremely good even with it terminating at Heights and not displacing the CR stops. The thing about Needham is that the density there is all north-south oriented into Newton while the service cuts off at Heights and runs east-west. The vast expanse of Cutler Park coupled with 128 and no connecting local street grid makes West Roxbury a whole different universe from them. And vice-versa when FH-W. Rox is east-west orientation with N-S affinity to Brookline not Newton/Needham. There's no buses going between the two halves of the line because the main east-west roads out of Needham like Great Plain Ave. and 135 all orient to Dedham not the city. So the primary CR ridership in Needham is 9-5'ers going to the central business district. The point-to-point'ers who are out all day have to deal with the godawful oversaddled 59 bus up Highland Ave. where all the density trends.
It's very much a misfit configuration in addition to being choked for slots. That's why 70 years worth of proposals have all involved separating it into N-S Needham and E-W Boston flanks that no longer t touch. Because they don't need to if the one-seater to downtown travels along the people's natural travel orientations.
