Reasonable Transit Pitches

[bigeman312]

Exactly this. Staggering the platforms isn't necessarily what kills the idea of dropping a side platform (in fact, it's probably the most feasible way to squeeze one in if you drop it by the lower busway/parking lot where the trench is open).

I'm just not sure 1) how you tie it into the main station (because having it egress into the busway isn't exactly tying it in the way the existing platforms are) and 2) what the price tag would be for everything (since you'd probably have to start messing with the Ukraine Way crossovers if you put a platform that far south)

Looking at it more closely, there is more room between the NEC and MetroMark than I originally thought. Just a rough eyeball of what could be done (apologies for the poor mockup quality, as I have little design experience of this type):

Honestly, this may be more reasonable than crazy.

The most reasonable first step would still be a no-build addition of some Forest Hills outbound stops to the Franklin/Providence/Stoughton Lines (possibly starting with off-peak Stoughton Line trains that already stop at Hyde Park).

But it appears that this platform could be added entirely with a cut (and partial or full cover), with no structures or roads above. The most meaningful entity cut during construction would be the multi-use trail access point. I don't love that, but given the bi-directional cycle track across the street, and a plethora of cycling and pedestrian infrastructure in the area, I think that section could be severed during construction, and slightly realigned if necessary around the expanded headhouse.

EDITED TO ADD: After examining the property lines on gis, it appears the MBTA owns approximately 55-60 feet of width from the MetroMark property line to the NEC trench. Am I taking crazy pills or is this a bona-fide plausible transit pitch?

 

[F-Line to Dudley]

There is a plan to extend the third track from Readville to Canton Junction. The fourth track from Forest Hills to Readville would help to make Forest Hills a more viable commuter stop.

No, it wouldn't...it would make it worse. See this post referenced earlier in the discussion: http://archboston.com/community/threads/reasonable-transit-pitches.4187/post-394737.

Right now the outermost track on the island platform is Needham-only. Needham can be at a dead-stop there without blocking any traffic on thru NEC tracks, and it's only when there's double-occupancy on both sides of the island that the NEC is in any way impaired. Re-adding Track 4 makes both sides of the island thru NEC tracks, meaning any stopped Needham train is going to be blocking a thru NEC track. It then takes escalating crossover games to weave around stopped trains, and that gets progressively harder as everyone's service levels increase. It's why Needham gets boxed-into stet levels of service forever in spite of Regional Rail'ification, because all the Providence/Stoughton/Franklin trains weaving around end up causing conflicts galore until the area bookending FH Station and its interlockings are completely saturated. Saturation comes sooner than ever the more Providence/Stoughton/Franklins you task with stopping there.

This isn't fixable unless you widen out the cavern for a platform setup that minimizes crossover movements...like side platforms on Tracks 1 & 4 only for Providence trains so the center tracks are always clear, or an extra-bored turnout platform for Needham that's completely separated from the NEC works after Track 4 comes back. All of which are megabucks solutions. If it's going to have to cost megabucks, there better be a provable return-on-ridership for it...something we haven't exactly quantified here with all the talk on "reasonableness".

 

[bigeman312]

F-Line, would the (three-track with side-platforms) proposal work in a world without the Needham Line (ie OLX, GLX, or some other solution that uncouples the Needham Line from the NEC)?

 

[F-Line to Dudley]

F-Line, would the (three-track with side-platforms) proposal work in a world without the Needham Line (ie OLX, GLX, or some other solution that uncouples the Needham Line from the NEC)?

Yes. You could, if you built the side platform, keep stopping trains to the outside and skipping trains to the center express tracks just fine and dandy. The inner berth on the island would operationally go more-or-less disused, but that's it. It's the crossover movements that kill capacity. You aren't going to be able to mix and match Needhams that cross over (and potentially block one of the center tracks when forced to the inner island berth) with heaps of added service elsewhere. Something has to give.

FH doesn't need to go disused by any stretch. You just can't pulse it up to full-on Regional Rail utilization while the Needham gimp is still attached. Everything ends up choking on the crossover conflicts until you stop crossing over to excess.

 

[BostonBoy]

No, it wouldn't...it would make it worse. See this post referenced earlier in the discussion: http://archboston.com/community/threads/reasonable-transit-pitches.4187/post-394737.

Right now the outermost track on the island platform is Needham-only. Needham can be at a dead-stop there without blocking any traffic on thru NEC tracks, and it's only when there's double-occupancy on both sides of the island that the NEC is in any way impaired. Re-adding Track 4 makes both sides of the island thru NEC tracks, meaning any stopped Needham train is going to be blocking a thru NEC track. It then takes escalating crossover games to weave around stopped trains, and that gets progressively harder as everyone's service levels increase. It's why Needham gets boxed-into stet levels of service forever in spite of Regional Rail'ification, because all the Providence/Stoughton/Franklin trains weaving around end up causing conflicts galore until the area bookending FH Station and its interlockings are completely saturated. Saturation comes sooner than ever the more Providence/Stoughton/Franklins you task with stopping there.

This isn't fixable unless you widen out the cavern for a platform setup that minimizes crossover movements...like side platforms on Tracks 1 & 4 only for Providence trains so the center tracks are always clear, or an extra-bored turnout platform for Needham that's completely separated from the NEC works after Track 4 comes back. All of which are megabucks solutions. If it's going to have to cost megabucks, there better be a provable return-on-ridership for it...something we haven't exactly quantified here with all the talk on "reasonableness".

 

[BostonBoy]

I don't get your logic. Adding capacity increases delays? Track 3 Forest Hills to Readville would give Franklin trains flexibility to crossover at Readville or Plains. Needham Trains could hold outside of the station (or Franklintrains could hold. Having track 3 doesn't automatically mean Amtrak will take it over. BTW the corridor should have been 4 tracked from the beginning.

 

[BostonBoy]

I don't get your logic. Adding capacity increases delays? Track 3 Forest Hills to Readville would give Franklin trains flexibility to crossover at Readville or Plains. Needham Trains could hold outside of the station (or Franklintrains could hold. Having track 3 doesn't automatically mean Amtrak will take it over. BTW the corridor should have been 4 tracked from the beginning.

Further Adding track no. three between Readville and Forest Hills would make tracks 3 and 4 commuter only while tracks 1 and 2 would be for Amtrak. One could add a station at Clarendon Hills. It would be just like Attleboro.

 

[F-Line to Dudley]

I don't get your logic. Adding capacity increases delays? Track 3 Forest Hills to Readville would give Franklin trains flexibility to crossover at Readville or Plains. Needham Trains could hold outside of the station (or Franklintrains could hold. Having track 3 doesn't automatically mean Amtrak will take it over. BTW the corridor should have been 4 tracked from the beginning.

It's not "my" logic. It's documented all over the place in NEC capacity studies done by both the T and Amtrak that excessive crossing over reduces capacity regardless of the additional tracks. The crossovers are slower than the mainline, and the mainline has revved up to >90 MPH at this point. It absolutely gets in Amtrak's way (as well as any Purple Line expresses) to have to mash all the way to one side, then mash all the way back...because the train that's doing the mashing-over is going to running way slow. It requires the train spacing to increase quite a bit on all tracks, and that ends up reducing capacity. You can add as many stations as you want, but there have to be express-past tracks unimpeded by trains crossing over to make that work. Amtrak is the enthroned dispatcher here, and for high speed trains it explicitly doesn't want to be bobbing and weaving all over the place. That means the burden is going to fall to the T to limit its crossover games.

Further Adding track no. three between Readville and Forest Hills would make tracks 3 and 4 commuter only while tracks 1 and 2 would be for Amtrak. One could add a station at Clarendon Hills. It would be just like Attleboro.

Again...not with all that crossing-over work. Refer back to the post I linked to. It has this diagram, copied below, showing the track layout @ FH when Track 4 is added:

The crossover layout is going to create conflicts. All 3 tracks are mixed/matched with the new Ruggles setup, so you will absolutely be having trains cutting over 2 or more tracks all the freaking time on both sides to get around.

Furthermore, the crossover games don't end here. The Rail Vision is proposing to boot the vast majority of the Franklin schedule over to the Fairmount Line to vacate the NEC outright, because that branch also messes things up with slow-speed crossing moves on what optimally should be a high-speed straightaway for Amtrak and any Purple expresses to sort their own pecking order. So the fact that you have mashing moves at BOTH Forest Hills and Hyde Park-Readville is extremely problematic. They've documented this to the nines with the Rail Vision and Amtrak's NEC Infrastructure Improvements Master Plan. The powers-that-be have decreed that this is unsustainable practice in the face of service increases, and that there should be a move to WAY LESS crossing over instead of way more.

The fact that you physically, if you wanted to force it, could cross over more is not relevant. Both T and Amtrak don't want that because of the limiting effects on finite capacity, and even if you could convince the T to toe a different line Amtrak being annointed dispatching lord is a veto that can't be overridden. As I said, you could feature FH on Providence/Stoughton trains all you wanted if there were a side platform on Track 1, Needham got the heave-ho, and Franklin got re-routed...because then nobody would have to cross over. But Needham needing to plow across tracks, and other lines needing to bob and weave all over the place to make it fit has already been rejected by the powers-that-be for its diminishing returns over time and incompatibilities with express timekeeping. If you want a solution for more Purple Line service @ FH, that solution is going to have to contour to these realities at whatever price contouring to these realities entails.

 

[BostonBoy]

It's not "my" logic. It's documented all over the place in NEC capacity studies done by both the T and Amtrak that excessive crossing over reduces capacity regardless of the additional tracks. The crossovers are slower than the mainline, and the mainline has revved up to >90 MPH at this point. It absolutely gets in Amtrak's way (as well as any Purple Line expresses) to have to mash all the way to one side, then mash all the way back...because the train that's doing the mashing-over is going to running way slow. It requires the train spacing to increase quite a bit on all tracks, and that ends up reducing capacity. You can add as many stations as you want, but there have to be express-past tracks unimpeded by trains crossing over to make that work. Amtrak is the enthroned dispatcher here, and for high speed trains it explicitly doesn't want to be bobbing and weaving all over the place. That means the burden is going to fall to the T to limit its crossover games.



Again...not with all that crossing-over work. Refer back to the post I linked to. It has this diagram, copied below, showing the track layout @ FH when Track 4 is added:

The crossover layout is going to create conflicts. All 3 tracks are mixed/matched with the new Ruggles setup, so you will absolutely be having trains cutting over 2 or more tracks all the freaking time on both sides to get around.

Furthermore, the crossover games don't end here. The Rail Vision is proposing to boot the vast majority of the Franklin schedule over to the Fairmount Line to vacate the NEC outright, because that branch also messes things up with slow-speed crossing moves on what optimally should be a high-speed straightaway for Amtrak and any Purple expresses to sort their own pecking order. So the fact that you have mashing moves at BOTH Forest Hills and Hyde Park-Readville is extremely problematic. They've documented this to the nines with the Rail Vision and Amtrak's NEC Infrastructure Improvements Master Plan. The powers-that-be have decreed that this is unsustainable practice in the face of service increases, and that there should be a move to WAY LESS crossing over instead of way more.

The fact that you physically, if you wanted to force it, could cross over more is not relevant. Both T and Amtrak don't want that because of the limiting effects on finite capacity, and even if you could convince the T to toe a different line Amtrak being annointed dispatching lord is a veto that can't be overridden. As I said, you could feature FH on Providence/Stoughton trains all you wanted if there were a side platform on Track 1, Needham got the heave-ho, and Franklin got re-routed...because then nobody would have to cross over. But Needham needing to plow across tracks, and other lines needing to bob and weave all over the place to make it fit has already been rejected by the powers-that-be for its diminishing returns over time and incompatibilities with express timekeeping. If you want a solution for more Purple Line service @ FH, that solution is going to have to contour to these realities at whatever price contouring to these realities entails.

Mr. F. I was thinking more my track 3 ( which is the existing Needham line station track) running north of the existing platform and track 4 merging to track 2 just east of Forest Hills. It may allow a platform on my proposed track 4, which would be the south track on your track chart. I think there may be room there to do that. Track no 2 would be the only track not to have a platform. (Retired railroader so my compass points are timetable driven)

 

[BostonBoy]

Mr. F. I was thinking more my track 3 ( which is the existing Needham line station track) running north of the existing platform and track 4 merging to track 2 just east of Forest Hills. It may allow a platform on my proposed track 4, which would be the south track on your track chart. I think there may be room there to do that. Track no 2 would be the only track not to have a platform. (Retired railroader so my compass points are timetable driven)

The track 4 would allow Amtrak trains to overtake local traffic before entering the SW Corridor. The New platform at Ruggles removes the opposing crossover at Plains for eastbound trains stopping at Ruggles. The four tracks where I propose them take Westbound Locals off track 1 all the way to Canton Jct ( assuming track 3 is extended) The only conflict is an eastbound move for Needham trains headed to Boston, which already exists. East bound Needham traffic could use track 3 to Cove when westbound locals are able to follow Amtrak traffic out of South Station on track 1. I think it expands capacity while removing cross over traffic

 

[BostonBoy]

And, regarding Readville, if Franklin passengers start demanding a one seat ride to Bay Bay, there is no better place to put a flyover from the Franklin to my proposed track 4 than at Readville. Plenty of room.

 

[F-Line to Dudley]

And, regarding Readville, if Franklin passengers start demanding a one seat ride to Bay Bay, there is no better place to put a flyover from the Franklin to my proposed track 4 than at Readville. Plenty of room.

Can't even begin to comprehend what you're talking about here. With all the surrounding street overpasses and multi-level junctioning rail infrastructure surrounding Readville on all sides there is no room anywhere for constructing flying junctions at FRA grades. Franklin is always going to junction with the NEC on the west (Tks. 3 & 4) side, and that is absolutely a problem for trains being forced to cross over...compounded by the Needham trains needing to cross over a short distance up. As long as you have 2 full-service branchlines junctioning flat off a western trajectory requiring multiple crossover moves in a 4-mile/3-station span where the layer-cake traffic profile of the NEC requires for that span to be a sorting space for service classes of divergent speed profiles, you're going to have conflicts that escalate with increasing traffic on each tier of the layer cake. That's inescapable. Something has to give, because not all mouths can feed from the same trough the way this is set up.

Whether "your" Track 4 and crossover layout are some ingenious improvement over everything under the sun the official parties have studied or not, remember...the official parties have had "their" proposed track layout ratified for 11 years now ever since the NECIIMP document (which that previous illustration was direct-sourced from) was released by Amtrak with the MBTA's and MassDOT's co-sign. Those parties all foresee conflict-city on the NEC with the Rail Vision and 2030+ Amtrak volumes being simultaneously fed through it, and are the ones calling for evasive action by culling the branches via other equitable means. "Their" Track 4 is ultimately going to be the one that matters, whether "yours" is any improvement or not on a Train Sim plot.


To reiterate: there is nothing wrong with Providence/Stoughton trains picking up FH with the side platform on Tk. 1, because it can all be done without crossing over. It's the presence of Needham and to lesser extent Franklin that gum up the works, because those are the ones that have no recourse but to lean hard on the crossover games. If more Purple Line service to FH is an aspirational thing (I'm not really sure the ridership says it is, but it could be)...then we need to be working on getting Needham and Franklin out of the way and cleaning up the crossover games. A 'more perfect kludge' of immaculate crossover placement isn't going to bring pure harmony here where any other setup is chaos. That's a lot of train-sim studying from official sources that would be upended in an "if only for this one neat trick I came up with..." scenario. I get that there's some turf warrage with Amtrak being the dispatcher that may or may not be influencing the presentation around the severity of conflicts, but when both agencies' traffic modeling bullseye this area as conflict-city under the reference Rail Vision + AMTK 2030 traffic levels...it's pretty unlikely they're bald-faced lying to us or sleeping on some ingenious quick-and-easy fix. After all, the state most definitely does not want to build OLX even if you dragged them over hot coals. The fact that they're saying it might be necessary **in spite of their innate revulsion to it** definitely telegraphs their underlying level of concern that the NEC is up to the task of handling full Regional Rail service levels with its incumbent branch membership. If they could make everything harmonious with a simple "your/their" crossover tweak instead of letting slip "Welp, we might actually have to rapid-transitize Needham after all"...don't you think they would've been pushing that solution with highlights long ago???

 

[BostonBoy]

With all due respect Mr F Line. All the professionals thought three tracks and platforms on tracks 1 and three at Forest Hills and Ruggles would suffice., but they had to build a platform on track 2 at Ruggles...... And they had to change the signal system on track 2 there too. ( I was there). A little personal background. 42 years railroading, in operations. I am not an expert on track geometry , but I know experts can figure it out when they need to, if they are tasked with an objective. I know there are always limitations, but sometimes even the experts should pause, and listen. BTW. I am a huge fan. I do not know how you have so much knowledge of the landscape. My expertise is confined to the territory on which I was qualified. Please do not take any of my statements as a personal affront.

 

[BostonBoy]

Looking back at my posts, I think I have to backtrack, and retract. I am not advocating making Forest Hills a Commuter stop as much as changing the right of way to improve capacity. My bias is towards improving Amtrak's speeds and access through the SW Corridor.

 

[BostonBoy]

I wish I was savvy enough to portray my ideas in graphics that showed my thoughts . But I will try to show them with my words. I Propose running mainline track 3 to where the Needham line now tracks on the platform at Forest Hills. The Needham line would divert directly from that track. It would also proceed west on the Southwest Corridor. Mainline track no 1 would run so that it platformed at Forest Hills. Mainline Track no 2 would run through Plains and Forest adjacent to track no. 1. the new track no. 4 would merge with tk 2 within the confines of Forest and Plains

 

[BostonBoy]

Mr F . I keep looking at your schematic of Forest and see what I consider a huge error. The Needham Branch is drawn as if it is a double track main line merging to a triple track main line. The Needham Branch is.... a branch line! It needs only to connect with a single track at Forest Hills. ( That is how it was run when I was conducting Budd cars between Needham and So. Station) Take out the crossovers accommodating inbound moves to Boston. Have that branch connect with mainline track 3, which would run north of the platform at Forest Hills. That gives you room to fit three other tracks south of the platform at Forest Hills.

 

[Brattle Loop]

Mr F . I keep looking at your schematic of Forest and see what I consider a huge error. The Needham Branch is drawn as if it is a double track main line merging to a triple track main line. The Needham Branch is.... a branch line! It needs only to connect with a single track at Forest Hills. ( That is how it was run when I was conducting Budd cars between Needham and So. Station) Take out the crossovers accommodating inbound moves to Boston. Have that branch connect with mainline track 3, which would run north of the platform at Forest Hills. That gives you room to fit three other tracks south of the platform at Forest Hills.

I'm having an enormously hard time wrapping my head around all of this (though some of that is I don't quite have a handle on the track numbering at Forest Hills). It sounds to me like you're suggesting that the current two-track Needham split at Forest Hills interlocking be consolidated to a single track connecting to the northernmost track at Forest Hills station (which would be the fourth NEC track...at the bottom of the diagram? If the bottom of F-Line's diagram is north, which I hope it is because otherwise I'm even more confused.) That would make Needham...worse by making meets that much trickier. (I used to regularly ride a Fitchburg Line train that had a scheduled stop to wait for an inbound to clear the single track through Waltham, which was very annoying, hence my hesitation at any plan that deliberately introduces more blocks like this, particularly as any train waiting to enter/leave the branch would face the extra delay of waiting for it to serve the station and move on.)

If I understand correctly, Needham already uses the northernmost platform by preference except where meets and such mean that they have to use the inner platform on Track 3. Cutting Needham off Track 3 doesn't actually give you more space, it just means you have to stage your meets somewhere else (and, um, doing that on the NEC seems like it'd make things worse, so you'd have to do it on the branch, which makes their service worse and gets you...barely more than you have already. That might be slightly beside the point, because I think the point is that the outer platform connected to the 4th NEC track is going to be needed for getting the slower NEC stuff out of the way of Amtrak and the Providence expresses, meaning that Needham's going to have to be more opportunistic in which platform track it uses, meaning that cutting off its access to half the platform would actually break the line entirely. If all you accomplish is screwing Needham up without actually opening up more room for the CR trains to get out of Amtrak's way, that's not a success.

 

[BostonBoy]

I'm having an enormously hard time wrapping my head around all of this (though some of that is I don't quite have a handle on the track numbering at Forest Hills). It sounds to me like you're suggesting that the current two-track Needham split at Forest Hills interlocking be consolidated to a single track connecting to the northernmost track at Forest Hills station (which would be the fourth NEC track...at the bottom of the diagram? If the bottom of F-Line's diagram is north, which I hope it is because otherwise I'm even more confused.) That would make Needham...worse by making meets that much trickier. (I used to regularly ride a Fitchburg Line train that had a scheduled stop to wait for an inbound to clear the single track through Waltham, which was very annoying, hence my hesitation at any plan that deliberately introduces more blocks like this, particularly as any train waiting to enter/leave the branch would face the extra delay of waiting for it to serve the station and move on.)

If I understand correctly, Needham already uses the northernmost platform by preference except where meets and such mean that they have to use the inner platform on Track 3. Cutting Needham off Track 3 doesn't actually give you more space, it just means you have to stage your meets somewhere else (and, um, doing that on the NEC seems like it'd make things worse, so you'd have to do it on the branch, which makes their service worse and gets you...barely more than you have already. That might be slightly beside the point, because I think the point is that the outer platform connected to the 4th NEC track is going to be needed for getting the slower NEC stuff out of the way of Amtrak and the Providence expresses, meaning that Needham's going to have to be more opportunistic in which platform track it uses, meaning that cutting off its access to half the platform would actually break the line entirely. If all you accomplish is screwing Needham up without actually opening up more room for the CR trains to get out of Amtrak's way, that's not a success.

The railroad's timetable direction for these tracks is east and west. Back Bay station is towards the left of the diagram; east of Forest Hills.In the diagram Mr F supplied, the top track is no. 2 descending to 1, 3 , and the bottom track is actually the Needham branch. That track which is now the Needham Branch would be Mainline track three and run all the way to Rte 128. The Needham branch would join track no. three west of the platform and do its station work on track No 3 only, the tracks would be re designated 1, 2, and 4. track no 4 would=end east of the platform at Plains interlocking. The Needham line would only access Forest Hills station from the re-designated track no 3. could run east on track 3 toan interlocking east of Back Bay Station or cross over at Plains Interlocking ( which is just east of Forest Hills Station) as it does now. There are two tracks west of the station on the Needham Branch That is where the Needham trains would make them. At this time I do not believe there are any meets on the Needham Branch. As far as adding capacity here, remember the Amtrak is expecting to increase its Acela service with the new, expanded fleet, and eventually I think that South Coast will be heading to the Corridor. I cannot tell you how many times we chugged along on the Acela, following a Providence or Stoughton Local ( especially if they were stopping at Ruggles ,but that's finally over ) Down Sharon Hill and all the way to Boston because we could not get around them.

 

[Brattle Loop]

The railroad's timetable direction for these tracks is east and west. Back Bay station is towards the left of the diagram; east of Forest Hills.In the diagram Mr F supplied, the top track is no. 2 descending to 1, 3 , and the bottom track is actually the Needham branch. That track which is now the Needham Branch would be Mainline track three and run all the way to Rte 128. The Needham branch would join track no. three west of the platform and do its station work on track No 3 only, the tracks would be re designated 1, 2, and 4. track no 4 would=end east of the platform at Plains interlocking. The Needham line would only access Forest Hills station from the re-designated track no 3. could run east on track 3 toan interlocking east of Back Bay Station or cross over at Plains Interlocking ( which is just east of Forest Hills Station) as it does now. There are two tracks west of the station on the Needham Branch That is where the Needham trains would make them. At this time I do not believe there are any meets on the Needham Branch. As far as adding capacity here, remember the Amtrak is expecting to increase its Acela service with the new, expanded fleet, and eventually I think that South Coast will be heading to the Corridor. I cannot tell you how many times we chugged along on the Acela, following a Providence or Stoughton Local ( especially if they were stopping at Ruggles ,but that's finally over ) Down Sharon Hill and all the way to Boston because we could not get around them.

Still confused.

There are four tracks at Forest Hills currently, Tracks 2, 1, 3, and 5. Tracks 2 and 1 do not serve the existing platform, Track 3 serves the platform from the NEC and the Needham Line, and Track 5 serves the Needham Line but does not connect to the NEC west of FH (i.e. there's no connection from NEC Track 3 to Track 5 at Forest interlocking). A few pages back, F-Line detailed that Needham already uses Track 5 preferentially, with only limited use of Track 3 for the Needham trains when operational necessity requires it. The implication of that fact is that if you cut off Needham's access to Track 3 (I'm using the current numbering to avoid confusing myself even more) you don't actually gain much of anything because Needham tends to avoid that track anyway (presumably because Needham trains serve FH, so having them stop on the corridor is the problem).

When NEC Track 4 is built it will connect at Forest interlocking to what is currently Track 5, the northernmost (Needham) platform track at Forest Hills station. If I understand correctly, the point of the 4th NEC track and the accompanying improvement at Forest interlocking is to help sort the NEC traffic and get the CR out of Amtrak's way. Force-severing Needham from Track 3 and cementing all of its service into Track 5 seems like it would completely defeat the purpose of the project, which is to provide more opportunities to move trains out of the way as-necessary.

So, yeah, still confused.

 

[BostonBoy]

Still confused.

There are four tracks at Forest Hills currently, Tracks 2, 1, 3, and 5. Tracks 2 and 1 do not serve the existing platform, Track 3 serves the platform from the NEC and the Needham Line, and Track 5 serves the Needham Line but does not connect to the NEC west of FH (i.e. there's no connection from NEC Track 3 to Track 5 at Forest interlocking). A few pages back, F-Line detailed that Needham already uses Track 5 preferentially, with only limited use of Track 3 for the Needham trains when operational necessity requires it. The implication of that fact is that if you cut off Needham's access to Track 3 (I'm using the current numbering to avoid confusing myself even more) you don't actually gain much of anything because Needham tends to avoid that track anyway (presumably because Needham trains serve FH, so having them stop on the corridor is the problem).

When NEC Track 4 is built it will connect at Forest interlocking to what is currently Track 5, the northernmost (Needham) platform track at Forest Hills station. If I understand correctly, the point of the 4th NEC track and the accompanying improvement at Forest interlocking is to help sort the NEC traffic and get the CR out of Amtrak's way. Force-severing Needham from Track 3 and cementing all of its service into Track 5 seems like it would completely defeat the purpose of the project, which is to provide more opportunities to move trains out of the way as-necessary.

So, yeah, still confused.

OOPS sorry! Track four will connect to track 2