Acela & Amtrak NEC (HSR BOS-NYP-WAS and branches only)

[themissinglink]

Amtrak representatives to hold two community meetings on bridge replacement projects over Bush and Gunpowder rivers​

Amtrak representatives will meet with community members and local waterway users on Aug. 18 in Joppatowne to present updates and address public concerns regarding upcoming replacement projects for two rail bridges over the Bush and Gunpowder rivers.
[...]
The projects involve replacing existing aging drawbridges with fixed structures designed to accommodate higher train speeds along Amtrak’s Northeast Corridor. Under current plans, the Bush River Bridge will be replaced with a fixed bridge featuring a 30-foot vertical clearance above mean high tide to support train speeds up to 160 mph. The Gunpowder River Bridge will be replaced with a fixed structure offering 15 feet of vertical clearance above mean high tide to support speeds of 145 mph or higher. Horizontal clearances for both channels are slated to remain unchanged.

I feel like the Bush, Gunpowder, and Susquehanna bridge replacement projects have gone a bit under the radar. Once the bridges are replaced, the Acela will be able to go 160 MPH for part of the trip in Maryland. There has also been talk about future speed improvements in Delaware to allow for 160 MPH (the current limit is 135 MPH). These speed increases will significantly improve the Acela's performance between Philadelphia and Washington.

Also, construction began last week on the TIME-1 project in Connecticut, which will increase the speed limit from 70 MPH to 90 MPH on a three-mile stretch of track in Bridgeport and Stratford:

Connecticut begins project to shave 25 minutes off Metro-North by 2035​

Governor Ned Lamont SOM ’80 and state transportation officials broke ground Monday on a $1.6 billion effort to modernize the Metro-North Railroad’s New Haven Line, the busiest commuter rail service in the country.
The initiative, known as TIME-1, is the biggest component of TIME FOR CT, a major capital investment program that Lamont introduced in 2021 to improve Connecticut’s rail infrastructure. Once all three phases of TIME-1 are complete in 2035, state officials say, passengers traveling between New Haven and New York City will save about 25 minutes on a trip that typically takes two hours.
[...]
As part of the first phase, the state’s transportation agency is modernizing track and signal infrastructure, as well as installing new overhead wires and structures that power trains. The upgrades will let Metro-North trains reach 90 miles per hour in parts of the corridor where the current maximum speed is only 70 miles per hour.

The future of the Northeast Corridor is looking good. There are a lot of projects planned or under construction that will increase speeds and improve reliability:

Project Name​	Location​	Speed Increase​	Estimated Completion Date​	Project Status​
Portal North Bridge	Kearny & Secaucus, NJ	60 MPH to 90 MPH	2026	Mostly complete, second track to be connected by November
East River Tunnels rehabilitation project	New York City	No speed increase	2027	Under construction
Dock Bridge rehabilitation project	Newark & Harrison, NJ	No speed increase	2028	Under construction
TIME-1 speed improvement project	Bridgeport to Stratford, CT	70 MPH to 90 MPH	2029	Under construction, broke ground on 8/3/26
Walk Bridge replacement project	Norwalk, CT	30 MPH to 45 MPH	2030	Under construction
Connecticut River Bridge replacement project	Old Saybrook & Old Lyme, CT	45 MPH to 70 MPH	2031	Under construction
Saugatuck River Bridge replacement project	Westport, CT	45 MPH to 90 MPH	2033	Groundbreaking planned for 2030
Pelham Bay Bridge replacement project	New York City	45 MPH to 70 MPH	2034	Groundbreaking planned for 2029
Bush River Bridge replacement project	Perryman, MD	125 MPH to 160 MPH	2034	Groundbreaking planned for 2028
Sawtooth Bridges replacement project	Kearny, NJ	60 MPH to 90 MPH	2035	Under construction
Gunpowder River Bridge replacement project	Chase, MD	125 MPH to 145 MPH (or higher)	2036	Groundbreaking planned for 2028
Frederick Douglass Tunnel (B&P Tunnel replacement)	Baltimore, MD	30 MPH to 110 MPH	2036	Under construction
Devon Bridge replacement project	Milford, CT	40 MPH to 70 MPH	2036	Groundbreaking planned for 2030
Susquehanna River Bridge replacement project	Perryville & Havre de Grace, MD	90 MPH to 160 MPH (south bridge) & 125 MPH (north bridge)	2036	Groundbreaking was planned for 2025 but did not occur
Gateway Program	New York City & Jersey City, NJ	Capacity increase, no speed increase	2035 (new tunnel), 2038 (rehabilitation of old tunnels)	Under construction

The Northeast Corridor will be in much better shape by the end of the 2030s, but there's still a lot left to be desired. The Cos Cob bridge replacement project is planned but unfunded, with no estimates for groundbreaking or completion. I don't think design work has even started for that one. The Shell Interlocking grade separation project in New Rochelle is badly needed, but it's not currently planned or funded. Grade-separating some of the crossings in Connecticut (especially the Miner Lane crossing) is also badly needed, but I'm not aware of any serious or funded plans to eliminate them. I'm also not sure if crossing eliminations in CT will allow for further speed increases or not. The Readville-to-Canton third-track project is also important, but I'm not sure if there's any funding allocated for it. I haven't been able to find anything about when it will break ground or be completed. Restoring the fourth track through Milford, CT is also very important, but it still lacks funding for design and construction. Additionally, Amtrak needs to finish the constant-tension catenary project in New Jersey, so that the Acela can travel at 160 MPH instead of 135 MPH. They finished installing the constant-tension catenary between New Brunswick and Princeton Junction in 2022, but AFAIK there's been no further catenary work done between Princeton Junction and Trenton. Once the second half of the project is completed, the stretch of track between New Brunswick and Trenton will be the longest continuous stretch of 160 MPH track on the entire Northeast Corridor.

 

[Scalziand]

I still find it frustrating that some of the new bridges(Looking at you Pelham Bay , Devon and Connecticut River Bridges) only have design speeds of 70 mph when 90 mph would be appropriate. I hope that the Devon Bridge can get uprated to 90mph once the TIME-1 improvements are completed since it's more or less on tangent track anyway. Unfortunately Pelham Bay and Connecticut River Bridges are locking in slower speed curves on the approaches.

 

[themissinglink]

I still find it frustrating that some of the new bridges(Looking at you Pelham Bay , Devon and Connecticut River Bridges) only have design speeds of 70 mph when 90 mph would be appropriate. I hope that the Devon Bridge can get uprated to 90mph once the TIME-1 improvements are completed since it's more or less on tangent track anyway. Unfortunately Pelham Bay and Connecticut River Bridges are locking in slower speed curves on the approaches.

Agreed. I wonder why the new Devon Bridge won't be able to support speeds over 70 MPH, especially considering the estimated $3B price tag...

As for the Pelham Bay Bridge replacement, it was originally envisioned to support speeds up to 110 MPH. I assume the nearby curves are to blame for the planned 70 MPH limit.

 

[F-Line to Dudley]

Agreed. I wonder why the new Devon Bridge won't be able to support speeds over 70 MPH, especially considering the estimated $3B price tag...

As for the Pehlam Bay Bridge replacement, it was originally envisioned to support speeds up to 110 MPH. I assume the nearby curves are to blame for the planned 70 MPH limit.

A 100 MPH zone ends at the north end of the Pelham Bridge slow zone, so southbound trains could definitely go at a higher rate of speed. But there's a 60 MPH curve restriction about a half-mile to the south where the ROW starts S-curving back and forth for a few miles, so northbound trains wouldn't ever be doing more than about 70 to begin with by the time they reach the bridge. They probably wouldn't have gotten much bang-for-buck doing any higher design speed.

Devon is bookended by long zones of 75 MPH speed limits, though those zones are the very ones TIME-1 is targeting for 90 MPH uprates. I'm confused as to why that one is being given such a low design speed.

CT River has enough landfill on both approach sides that the trajectory is environmentally really, really locked in. 90 MPH restricted curve immediately east of the bridge, 70 MPH restricted curve immediately west of it amid an overall 110 MPH zone. Southbound trains might be able to coast a *little* bit higher if they're not slowing for an Old Saybrook station stop, but no northbound train is going to ever do >70 given how close the curve is to the bridge (and anything stopping at Old Saybrook is going to be going much, much slower in acceleration at the bridge). Most likely another minimal bang-for-buck situation trying for a higher bridge speed limit.

 

[sneijder]

Amtrak representatives to hold two community meetings on bridge replacement projects over Bush and Gunpowder rivers​

I feel like the Bush, Gunpowder, and Susquehanna bridge replacement projects have gone a bit under the radar. Once the bridges are replaced, the Acela will be able to go 160 MPH for part of the trip in Maryland. There has also been talk about future speed improvements in Delaware to allow for 160 MPH (the current limit is 135 MPH). These speed increases will significantly improve the Acela's performance between Philadelphia and Washington.

Also, construction began last week on the TIME-1 project in Connecticut, which will increase the speed limit from 70 MPH to 90 MPH on a three-mile stretch of track in Bridgeport and Stratford:

Connecticut begins project to shave 25 minutes off Metro-North by 2035​

The future of the Northeast Corridor is looking good. There are a lot of projects planned or under construction that will increase speeds and improve reliability:

Project Name​	Location​	Speed Increase​	Estimated Completion Date​	Project Status​
Portal North Bridge	Kearny & Secaucus, NJ	60 MPH to 90 MPH	2026	Mostly complete, second track to be connected by November
East River Tunnels rehabilitation project	New York City	No speed increase	2027	Under construction
Dock Bridge rehabilitation project	Newark & Harrison, NJ	No speed increase	2028	Under construction
TIME-1 speed improvement project	Bridgeport to Stratford, CT	70 MPH to 90 MPH	2029	Under construction, broke ground on 8/3/26
Walk Bridge replacement project	Norwalk, CT	30 MPH to 45 MPH	2030	Under construction
Connecticut River Bridge replacement project	Old Saybrook & Old Lyme, CT	45 MPH to 70 MPH	2031	Under construction
Saugatuck River Bridge replacement project	Westport, CT	45 MPH to 90 MPH	2033	Groundbreaking planned for 2030
Pelham Bay Bridge replacement project	New York City	45 MPH to 70 MPH	2034	Groundbreaking planned for 2029
Bush River Bridge replacement project	Perryman, MD	125 MPH to 160 MPH	2034	Groundbreaking planned for 2028
Sawtooth Bridges replacement project	Kearny, NJ	60 MPH to 90 MPH	2035	Under construction
Gunpowder River Bridge replacement project	Chase, MD	125 MPH to 145 MPH (or higher)	2036	Groundbreaking planned for 2028
Frederick Douglass Tunnel (B&P Tunnel replacement)	Baltimore, MD	30 MPH to 110 MPH	2036	Under construction
Devon Bridge replacement project	Milford, CT	40 MPH to 70 MPH	2036	Groundbreaking planned for 2030
Susquehanna River Bridge replacement project	Perryville & Havre de Grace, MD	90 MPH to 160 MPH (south bridge) & 125 MPH (north bridge)	2036	Groundbreaking was planned for 2025 but did not occur
Gateway Program	New York City & Jersey City, NJ	Capacity increase, no speed increase	2035 (new tunnel), 2038 (rehabilitation of old tunnels)	Under construction

The Northeast Corridor will be in much better shape by the end of the 2030s, but there's still a lot left to be desired. The Cos Cob bridge replacement project is planned but unfunded, with no estimates for groundbreaking or completion. I don't think design work has even started for that one. The Shell Interlocking grade separation project in New Rochelle is badly needed, but it's not currently planned or funded. Grade-separating some of the crossings in Connecticut (especially the Miner Lane crossing) is also badly needed, but I'm not aware of any serious or funded plans to eliminate them. I'm also not sure if crossing eliminations in CT will allow for further speed increases or not. The Readville-to-Canton third-track project is also important, but I'm not sure if there's any funding allocated for it. I haven't been able to find anything about when it will break ground or be completed. Restoring the fourth track through Milford, CT is also very important, but it still lacks funding for design or construction. Additionally, Amtrak needs to finish the constant-tension catenary project in New Jersey, so that the Acela can travel at 160 MPH instead of 135 MPH. They finished installing the constant-tension catenary between New Brunswick and Princeton Junction in 2022, but AFAIK there's been no further catenary work done between Princeton Junction and Trenton. Once the second half of the project is completed, the stretch of track between New Brunswick and Trenton will be the longest continuous stretch of 160 MPH track on the entire Northeast Corridor.

It's wild how many 30-45mph zones there are in connecticut - I thought a lot of the slow Amtrak speeds were related to train dispatching/spacing with Metro North. With this punch list of upgrades + reduced padding, its crazy how much travel times could be improved just within the current ROW with better tracks. Maybe 3:15 from boston to NYP?

 

[JeffDowntown]

It's wild how many 30-45mph zones there are in connecticut - I thought a lot of the slow Amtrak speeds were related to train dispatching/spacing with Metro North. With this punch list of upgrades + reduced padding, its crazy how much travel times could be improved just within the current ROW with better tracks. Maybe 3:15 from boston to NYP?

I could be wrong, but I suspect you are going to have a hard time achieving much higher speeds while working around all the Metro North traffic. It may be one reason why improving the track speed has not been a priority.

 

[sneijder]

I could be wrong, but I suspect you are going to have a hard time achieving much higher speeds while working around all the Metro North traffic. It may be one reason why improving the track speed has not been a priority.

again not a rail engineer, but if you raised all the 30-45mph zones up to 75-90mph, wouldn't all trains (metro-north and otherwise) clear the signal blocks faster resulting in fewer traffic backups as well?

this is assuming we have 4 functional tracks along the length of new rochelle <> new haven, where all local stop traffic runs on the outer tracks and amtrak + metro north expresses run on the inner tracks.

 

[themissinglink]

I wonder if there's enough room along the ROW for five (or even six) tracks between West Haven and Milford. There are a few spots where it looks like there's more than enough room for additional tracks... but I'm not sure if there's enough continuous room for extra tracks the whole way between the two stations. The 6.2-mile stretch between West Haven and Milford is mostly straight; extra tracks would allow Amtrak trains to pass Metro North trains at 100+ MPH.

 

[JeffDowntown]

again not a rail engineer, but if you raised all the 30-45mph zones up to 75-90mph, wouldn't all trains (metro-north and otherwise) clear the signal blocks faster resulting in fewer traffic backups as well?

this is assuming we have 4 functional tracks along the length of new rochelle <> new haven, where all local stop traffic runs on the outer tracks and amtrak + metro north expresses run on the inner tracks.

I suspect the answer is "maybe". It rather assumes that Metro-North plays nice with slots (MTA Metro-North controls dispatch -- and they do not have a reputation of playing nice). Metro-North trains typically have slotting priority, which could result in Metro-North using any speed improvements mostly for its own Express and Semi-express service slots, and not really helping Amtrak.

 

[F-Line to Dudley]

I wonder if there's enough room along the ROW for five (or even six) tracks between West Haven and Milford. There are a few spots where it looks like there's more than enough room for additional tracks... but I'm not sure if there's enough continuous room for extra tracks the whole way between the two stations. The 6.2-mile stretch between West Haven and Milford is mostly straight; extra tracks would allow Amtrak trains to pass Metro North trains at 100+ MPH.

Milford-New Haven is slightly under-capacity compared to the rest of the New Haven Line, and has the widest stop spacing and fastest average speeds on all tracks because of the wide stop spacing, so that's the last place there needs to be any more passing tracks. They're taking their sweet time restoring the last bit of 4th track through Milford because of this. Amtrak already deals with the least amount of congestion on this stretch, so its speeds--while not great topping out at 75--at least aren't slowed below that. If it's possible to expand the ROW for more tracks, they need it most badly Stamford-New Rochelle where the most service overlaps.

Bridgeport-New Haven also isn't being uprated to 90 MPH until the very last phases of TIME-1, and isn't funded yet. The most bang-for-buck is doing the uprate Stamford-Bridgeport, which is the focus of Phase 1.

I suspect the answer is "maybe". It rather assumes that Metro-North plays nice with slots (MTA Metro-North controls dispatch -- and they do not have a reputation of playing nice). Metro-North trains typically have slotting priority, which could result in Metro-North using any speed improvements mostly for its own Express and Semi-express service slots, and not really helping Amtrak.

TIME-1 includes installation of a much higher-density signaling system which will allow closer train spacing and fewer speed restrictions on trailing blocks when riding another train's taillights, and they're supposed to be installing new higher-speed crossovers and more of them to make mixing of semi-expresses and super-expresses more fluid. That'll end up helping everyone on speeds including Amtrak, and part of the service increase Metro-North is envisioning for itself involves more New Haven super-expresses that basically mimic Northeast Regional-like stop spacing. I doubt the Acelas are going to see anything truly earth-shattering out of it, but the project is definitely bigtime good news for the Regionals (especially in light of ConnDOT's plans to make Amtrak hourly to Hartford and Springfield via likely extension of the Keystone trains New York to Springfield).

 

[themissinglink]

A 100 MPH zone ends at the north end of the Pelham Bridge slow zone, so southbound trains could definitely go at a higher rate of speed. But there's a 60 MPH curve restriction about a half-mile to the south where the ROW starts S-curving back and forth for a few miles, so northbound trains wouldn't ever be doing more than about 70 to begin with by the time they reach the bridge. They probably wouldn't have gotten much bang-for-buck doing any higher design speed.

Devon is bookended by long zones of 75 MPH speed limits, though those zones are the very ones TIME-1 is targeting for 90 MPH uprates. I'm confused as to why that one is being given such a low design speed.

CT River has enough landfill on both approach sides that the trajectory is environmentally really, really locked in. 90 MPH restricted curve immediately east of the bridge, 70 MPH restricted curve immediately west of it amid an overall 110 MPH zone. Southbound trains might be able to coast a *little* bit higher if they're not slowing for an Old Saybrook station stop, but no northbound train is going to ever do >70 given how close the curve is to the bridge (and anything stopping at Old Saybrook is going to be going much, much slower in acceleration at the bridge). Most likely another minimal bang-for-buck situation trying for a higher bridge speed limit.

Do you know why the Walk Bridge replacement will have a 45 MPH speed limit? Is it because of the adjacent curve? 45 MPH is a lot better than 30 MPH, but it's still awfully slow...

 

[F-Line to Dudley]

Do you know why the Walk Bridge replacement will have a 45 MPH speed limit? Is it because of the adjacent curve? 45 MPH is a lot better than 30 MPH, but it's still awfully slow...

That immediate adjacent curve in/out of South Norwalk station is 45 MPH-restricted in a 70 MPH zone, so eastbound trains will be going no faster and the signal system will be automatically slowing westbound trains from to 45 while they're in-process of going over the bridge. Since the curve is in an extremely built-up area, there's no way of easing it to allow higher speeds. Therefore it would've been a waste to do a bridge design speed higher than that.

 

[themissinglink]

Milford-New Haven is slightly under-capacity compared to the rest of the New Haven Line, and has the widest stop spacing and fastest average speeds on all tracks because of the wide stop spacing, so that's the last place there needs to be any more passing tracks. They're taking their sweet time restoring the last bit of 4th track through Milford because of this. Amtrak already deals with the least amount of congestion on this stretch, so its speeds--while not great topping out at 75--at least aren't slowed below that. If it's possible to expand the ROW for more tracks, they need it most badly Stamford-New Rochelle where the most service overlaps.

Bridgeport-New Haven also isn't being uprated to 90 MPH until the very last phases of TIME-1, and isn't funded yet. The most bang-for-buck is doing the uprate Stamford-Bridgeport, which is the focus of Phase 1.

Is Class 6/110 MPH possible between Milford and New Haven after the fourth track is reactivated? Or is there too much train traffic for Amtrak to go over 90 MPH?

 

[F-Line to Dudley]

Is Class 6/110 MPH possible between Milford and New Haven after the fourth track is reactivated? Or is there too much train traffic for Amtrak to go over 90 MPH?

Milford Station is bookended by 60 MPH curves and the New Haven terminal district is 30 MPH, but the rest of it is unrestricted 75 MPH and fairly straight. In the absolute you could probably bump it to 125 MPH, but traffic levels even on the center express tracks wouldn't permit much more than 90 MPH unless you did a lot more high-speed crossovers. One thing Metro-North has absolutely shat the bed on is cost control for turnouts; they pay several times the world going rate for bespoke customized hardware, so they've been loathe to add more crossovers than they need for their own service. If they had better relations with Amtrak some compromise could probably be reached, but the two don't get along and Amtrak has a big enough laundry list of speed improvements it can self-implement on the southern NEC that it owns so they haven't been chomping at the bit to fight hand-to-hand with MNRR about high-speed crossover specs and installations.

The 4th track already is partially reactivated through West Haven. They strung up wire and fixed the speeds on 6 miles of old freight lead when they were replacing all the overhead about 10 years ago. The remaining 3-track gap is only about 3.8 miles from Devon Jct. to eastern Milford and only requires a rebuild of Milford Station (the southbound ADA platform currently sits on the Track 4 berth).

 

[BeansTheCat]

That immediate adjacent curve in/out of South Norwalk station is 45 MPH-restricted in a 70 MPH zone, so eastbound trains will be going no faster and the signal system will be automatically slowing westbound trains from to 45 while they're in-process of going over the bridge. Since the curve is in an extremely built-up area, there's no way of easing it to allow higher speeds. Therefore it would've been a waste to do a bridge design speed higher than that.

Looking at the 45 MPH curve just west of the Walk Bridge, the existing geometry seems like it could allow higher speeds. Let me start with a caveat: I did not measure this curve to determine the exact geometry, so this is mostly speculation. But the current geometry appears roughly as sharp as existing 70 MPH curves. Also, the curve can be extended over a newly rebuilt Walk Bridge to further smooth it out and raise speeds. That adjustment would require shifting the current 45 MPH track a smidge to the south, but as you can see below, that is almost entirely industrial land or part of the existing ROW. I have also been given the impression that Metro-North does not superelevate their tracks quite as much as they could, but don't know the full implications here.

More broadly, I'd like to NEC projects move to having a default minimum design speeds. These could vary by region, but the idea would be that any new track project would have to support speeds of X MPH. This would cause corridor-wide speeds to gradually increase as these types of rehabilitation and replacement projects are done. Some exceptions should be allowed, but the criteria needs to be strict. Approaches to stations where all trains stops or sufficiently large takings (in terms of money, homes, parkland, etc.) serve as examples.

 

[Scalziand]

New Haven to Providence Capacity Planning Study

newhavenprovidencestudy.com

New Haven-Providence Capacity Planning Study now has an official website with opportunities to sign up for their mailing list and submit comments. There’s also a version of the FAQ sheet I posted a month ago (a few posts up on this page) and their Outreach & Engagement Plan.

Got an email update for some outreach events this weekend:

The New Haven to Providence Capacity Planning Study team is hitting the road this weekend with two public pop-up events, and we'd love for you to stop by if you’re nearby. These events are part of an ongoing series, so you'll continue to see us around the study area in the coming weeks, raising awareness of the study and giving the public a chance to learn more, ask questions, and share feedback.

Last week, we held our first successful pop-up event at Ninigret Park in Charlestown, Rhode Island, during the Ninigret Summer Nights Concert and Movie event. Thank you to everyone who stopped by to speak with the project team and share their input, as well as to the Town of Charlestown for hosting us. We were glad to join this community event on short notice and appreciated the opportunity to connect directly with local residents.

This weekend, we’ll be back out in the community with two more pop-up events:​

• Saturday, August 15 from 9am to 5pm, Rocky Neck State Park, Connecticut
• Sunday, August 16 from 9:30am to 5:30pm, Scarborough North State Beach, Rhode Island

At both events, members of the project team will be available to share information about the study, answer questions, and hear feedback. We hope you can stop by and encourage you to share these upcoming events with interested residents, community organizations, and stakeholders. Please keep in mind that these state beaches can be quite busy during the summer, so parking areas may be busy and/or full at certain times.

As you know, Amtrak is conducting the New Haven to Providence Capacity Planning Study in partnership with Connecticut DOT, Rhode Island DOT, Massachusetts DOT, the Massachusetts Bay Transportation Authority, the Federal Railroad Administration, and the Northeast Corridor Commission. The study is evaluating alternatives to preserve and improve rail capacity and performance along the Northeast Corridor while carefully considering potential impacts on surrounding communities and the environment. Public input will play an important role in shaping the study and informing future recommendations.

We are also finalizing our schedule of pop-up events for September, so stay tuned for additional opportunities to connect with the project team, as well as more formal public engagement events later in the fall

If you are unable to attend this weekend, we encourage you to visit the project website to learn more about the study, sign up for project updates, and submit comments online.

Thank you for your continued support of the New Haven to Providence Capacity Planning Study and for helping us spread the word about these opportunities to get involved.


Sincerely,
The New Haven to Providence Capacity Planning Study Team​

 

[Scalziand]

Looking at the 45 MPH curve just west of the Walk Bridge, the existing geometry seems like it could allow higher speeds. Let me start with a caveat: I did not measure this curve to determine the exact geometry, so this is mostly speculation. But the current geometry appears roughly as sharp as existing 70 MPH curves. Also, the curve can be extended over a newly rebuilt Walk Bridge to further smooth it out and raise speeds. That adjustment would require shifting the current 45 MPH track a smidge to the south, but as you can see below, that is almost entirely industrial land or part of the existing ROW. I have also been given the impression that Metro-North does not superelevate their tracks quite as much as they could, but don't know the full implications here.

Part of the reason that MN doesn't superelevate to the full potential is because the track centers are too close together. The Bridgeport-Stratford project is increasing speeds while maintaining the same curve by increasing superelevation, which requires increasing the track spacing(~12.5 to ~14.5ft). In the Norwalk case, its also hard to superelevate tracks in a junction.