North East Corridor (NEC) speeds, new stations and state of repair

[jis]

Just by chance I came across this priceless document comparing the various PTC systems deployed on trackage used by Amtrak trains (other than I-ETMS). It includes a pretty complete description of ACSES and how V-ETMS (i.e. I-ETMS) is overlaid on ACSES trackage.

It actually comes from a stash of documents submitted as part of a case about FCC licensing of 220MHz and 900MHz bandwidth apparently. I have been unable to find an original at FRA yet, but it may be hiding somewhere and accessible from the internet that is yet to be discovered. Thought this might interest some who wish to dig deeper into the evolution of PTC

Amtrak PTCIP July 16 2010 (PDF)

Keep in mind that many details have changed since this was submitted to FRA. Indeed 900MHz is used now. But one can still get a pretty good idea on how Amtrak's various PTC implementations evolved. Amtrak was the first to broadly deploy a compliant PTC system in the US

 

[west point]

My take as stated before is ACSES is less vulnerable than any sattelite and / or GPS system. With all the debri left in low orbit the low orbits of communication and GPS low orbit are likely to degrade if debri hits one or more. This is becoming more likely as each new LEO shot looses part of its package. Already the ISS has been moved more than once due to close calls of larger objects. Its the small debri that willl do the deed. And space particlees can also cause problems. James Webb has alread taken a micro meteorite hit. Definitely up front costs and probably maintenance is more for ACSES.

 

[jis]

My take as stated before is ACSES is less vulnerable than any sattelite and / or GPS system. With all the debri left in low orbit the low orbits of communication and GPS low orbit are likely to degrade if debri hits one or more. This is becoming more likely as each new LEO shot looses part of its package. Already the ISS has been moved more than once due to close calls of larger objects. Its the small debri that willl do the deed. And space particlees can also cause problems. James Webb has alread taken a micro meteorite hit. Definitely up front costs and probably maintenance is more for ACSES.

Architecturally all PTC systems require a "Location Service" that enables a train and the dispatching system to determine the location of the train. ACSES (and its predecessor systems like TVM430 in France) has track circuits to locate the train for the dispatching system and track mounted transponders to tell the train where it is. I-ETMS, mainly because it is designed to operate on lines often with sparse service for hundreds of miles through the sticks reduces the cost of providing Location Service by using GPS, though there is nothing preventing them from using a hybrid location service should such a need arise.

The bottom line is that if GPS fails then inability to locate a few trains is going to be a problem that will not be among the top ten anyway, and it will take an incredibly large number of satellites to be knocked out at the same time which is statistically unlikely. Actually a good long Solar Storm disrupting radio communication is probably more of a risk than satellites getting knocked out by space junk or hostile missiles, and that will affect ACSES too.

 

[Touchdowntom9]

FRA regulations for superelevation. Most curves are at the max already. NEC already has a few exceptions too.

Along the NEC where is the real estate for additional tracks going to come from unless it is either additions to the present ROW or new ROW? For other routes, if one wants higher speed, it makes more sense to build new tracks for high speed service rather than for moving slower speed trains off of the less than ideal current ROWs at great cost. Of course where possible separation is a good idea, but is much harder to achieve where possible parallel routes are owned by different companies.

Actually the bigger problem on the NEC is inadequate track center distance and that is again impossible to increase in many place without extremely expensive work as the ROW is constrained by electrification poles. Basically the current electrification will have to be removed ROW expanded in width, tracks moved and then re-electrified.

The maximum capabilities of NEC under various scenarios and the corresponding costs are well known and speed will be increased opportunistically. But the NEC in its current form will never become a 300kph railroad. The goals are better specified in terms of end to end target run times. NY - Washington done in two hours would be basically at the edge of possibilities with very large investment short of new ROW in a lot of tunnels. More realistic would be 2.5 hours or so, which we will get to.

But realistically, other than bragging rights and railfan fomage what exactly is the added return from reducing running time from 3:00 to 2:45 to 2:30? Isn’t some of that incremental money better spent at getting say, the inland route to Boston upgraded, or the spine in Virginia upgraded and electrified? It is all a trade off.

Sorry to dig up an old post, but didnt the FRA amend their super elevation rules around 2013? Places like the Elizabeth S curve and Metuchen S curve seem like prime locations where you could crank the superelevation and keep the speed limit at or north of 100mph given how those are pretty gentle curves already. Or are you telling me that those curves have already been upgraded in recent years to hit that limit?

 

[GDRRiley]

It’s ridiculous that the United States’ high-speed rail line averages a speed that’s the same as driving. And if you add going to the station and boarding the train, the total trip time on the Acela is slower than driving.

thats what you would expect out of a 125-150mph railway. unless you've got no traffic and very few stops along with no slow points your going to average in the 70-90mph range. maybe 100 with a good EMU and few stops.

Sorry to dig up an old post, but didnt the FRA amend their super elevation rules around 2013? Places like the Elizabeth S curve and Metuchen S curve seem like prime locations where you could crank the superelevation and keep the speed limit at or north of 100mph given how those are pretty gentle curves already. Or are you telling me that those curves have already been upgraded in recent years to hit that limit?

normally you'll see superevlation on a pax line upto 6in with wavers that can go as high as 7in which isn't the highest we've had in the US a few sections in the northeast used 8in. Which is pretty close to in line with other countries.
however its unbalanced were FRA really shows how conservative it is, 3in is normal 4 is the limit with wavers vs 5-7in on some lines in Europe.

 

[MARC Rider]

It’s ridiculous that the United States’ high-speed rail line averages a speed that’s the same as driving. And if you add going to the station and boarding the train, the total trip time on the Acela is slower than driving.

What are you talking about? It takes me over 2 hours to drive from Baltimore to Philly, the driving time estimates from Google Maps are nonsense. The Northeast Regional does it in 1:15, The Acela does it in 1:05. Even accounting for driving to the station, it's faster to take the train. This is even more so between Baltimore and New York, especially since it seems that there's always a traffic jam on the GW Bridge or the two tunnels connecting New Jersey to Manhattan. I can't drive to New York faster than 4 hours, and that includes occasional minor violation of speed limits. The Northeast Regional takes me 2:40 to 2:50, and the Aclea takes 2:25. They're certainly fast enough for me to take day trips to New York, something I couldn't do in the good old days of the PRR.

 

[Acela150]

Sorry to dig up an old post, but didnt the FRA amend their super elevation rules around 2013? Places like the Elizabeth S curve and Metuchen S curve seem like prime locations where you could crank the superelevation and keep the speed limit at or north of 100mph given how those are pretty gentle curves already. Or are you telling me that those curves have already been upgraded in recent years to hit that limit?

The reverse curve at Elizabeth had the speeds increased with the ACSES rollout. But 100? That's a bit much.

 

[Touchdowntom9]

normally you'll see superevlation on a pax line upto 6in with wavers that can go as high as 7in which isn't the highest we've had in the US a few sections in the northeast used 8in. Which is pretty close to in line with other countries.
however its unbalanced were FRA really shows how conservative it is, 3in is normal 4 is the limit with wavers vs 5-7in on some lines in Europe.

Sorry, but to clarify are you saying the rules from the FRA are 3 inches maybe 4 inches (with Europe being 5-7 in), or are you saying that the NEC has a bunch of spots with 6-7 inches? Seems to me that the NEC would benefit in a massive way by having 6-7 inches wherever needed in order to keep speed limits at 100-125 for long stretch's rather than having such frequent slowdowns.

Do you know what Metuchen and Elizabeth are at in terms of super elevation right now? Because if they have room for more super elevation, you should never dip below 90mph once you leave the tunnels from NYP heading to Philly (once the new portal bridge is built)

 

[jis]

They don’t have room as far as superelevation goes. They are at max.

@GDRRiley is talking about underbalance of 3” to 4” not superelevation. NEC already has 6” to 7” superelevation.

There will be a few places with less than 90mph between Newark and Philly. Between Newark and New York speed limits are determined more by needs of maximizing throughput than minimizing running time of a subset of trains at least until the new tunnels and Portal South bridge is built and the quadruple tracking is completed. Which translates to probably not in my remaining lifetime

 

[GDRRiley]

Sorry, but to clarify are you saying the rules from the FRA are 3 inches maybe 4 inches (with Europe being 5-7 in), or are you saying that the NEC has a bunch of spots with 6-7 inches? Seems to me that the NEC would benefit in a massive way by having 6-7 inches wherever needed in order to keep speed limits at 100-125 for long stretch's rather than having such frequent slowdowns.

yes 3in is the standard for FRA unbalanced superevlation with special approval for 4in. Europe allows that to be 5-7in.

Do you know what Metuchen and Elizabeth are at in terms of super elevation right now? Because if they have room for more super elevation, you should never dip below 90mph once you leave the tunnels from NYP heading to Philly (once the new portal bridge is built)

I'm not aware of what the NEC has, I'm far more familiar with California and CAHSR

They don’t have room as far as superelevation goes. They are at max.

They could push the FRA to allow 8in but I'm not sure they've got track spacing for that

 

[Touchdowntom9]

yes 3in is the standard for FRA unbalanced superevlation with special approval for 4in. Europe allows that to be 5-7in.

I'm not aware of what the NEC has, I'm far more familiar with California and CAHSR


They could push the FRA to allow 8in but I'm not sure they've got track spacing for that

@GDRRiley and @jis thank you both for clarifying as I clearly was confused between superelevation vs unbalanced superelevation/cant deficiency.
Really sad that the FRA wont allow a few more inches of unbalance in key areas of the NEC where it would likely be perfectly safe (assuming Europe is correct) and save millions of people lots of minutes on their trips or commutes. Riding NJ transit from Princeton many times a week to nyc, that curve really kills the speed built up to that point and it feels like the curves are being taken far too conservatively (I've noticed we frequently dip to 40-45mph from 100mph). Bumping the top speed to 80 there would still be a huge improvement as the old Arrow IIIs wouldn't even have to slow down.

As far as I can tell, maximizing every sq inch of the existing infrastructure on the NEC is just as important as the capital projects, bridge replacements, new tunnels, new track etc

 

[GDRRiley]

Really sad that the FRA wont allow a few more inches of unbalance in key areas of the NEC where it would likely be perfectly safe (assuming Europe is correct) and save millions of people lots of minutes on their trips or commutes. Riding NJ transit from Princeton many times a week to nyc, that curve really kills the speed built up to that point and it feels like the curves are being taken far too conservatively (I've noticed we frequently dip to 40-45mph from 100mph). Bumping the top speed to 80 there would still be a huge improvement as the old Arrow IIIs wouldn't even have to slow down.

this table may help. from CASHR TM2.1.2
it also mentions the comparison to Europe and the Shinkansen.

As far as I can tell, maximizing every sq inch of the existing infrastructure on the NEC is just as important as the capital projects, bridge replacements, new tunnels, new track etc

We just also need to accept in some places acquiring more ROW is a must. The feds didn't care when it came to freeway and freeway expansion even now but its a really hard thing for rail to do.

Spoiler: table

 

[Bfputtzman]

yes 3in is the standard for FRA unbalanced superevlation with special approval for 4in. Europe allows that to be 5-7in.

I'm not aware of what the NEC has, I'm far more familiar with California and CAHSR


They could push the FRA to allow 8in but I'm not sure they've got track spacing for that

3” is standard UB for FRA. However, UB exceeding 3” (with no specific limit) is authorized under terms provided in 213.57d - namely car testing and certification. 213.57h(1) clarifies requirements for 3” < UB = < 5” and 213.57h(2) clarifies requirements for UB > 5”. Portions of Amtrak Cascades on BNSF are operated at 5” UB today utilizing standard single level Amtrak cars.

This next bit can use some fact checking: It is my understanding that most single level Amtrak cars are certified to 5” UB and that is an Amtrak design minimum requirement for future equipment. I also understand Amtrak operates some tilt equipment on the NEC at up to 7” UB.

To clarify, inches of super-elevation are in addition to inches of UB above.

 

[GDRRiley]

3” is standard UB for FRA. However, UB exceeding 3” (with no specific limit) is authorized under terms provided in 213.57d - namely car testing and certification. 213.57h(1) clarifies requirements for 3” < UB = < 5” and 213.57h(2) clarifies requirements for UB > 5”. Portions of Amtrak Cascades on BNSF are operated at 5” UB today utilizing standard single level Amtrak cars.

has 213.57 been revised sense 2008? my data is all being pulled from CAHSR so if it has then it would make sense its a bit out of date.
tilting should allow you to push higher than 5in UB which means as usual the FRA was pretty conservative when it allowed only 5 on tilting trains

This next bit can use some fact checking: It is my understanding that most single level Amtrak cars are certified to 5” UB and that is an Amtrak design minimum requirement for future equipment. I also understand Amtrak operates some tilt equipment on the NEC at up to 7” UB.

I have no idea where you'd find that info, its deep within contracts.

 

[west point]

do not forget that NYP - PHL has slower speed. As we all know PHL to Frankford JCT has various solwer sections.

 

[dlerach]

I believe that Amfleets are cleared for 5" unbalanced and the Acela is cleared for 7". I've heard as well that the Avelia Liberty could be cleared for 9", but it's my understanding that that testing/certification process is still ongoing.

 

[joelkfla]

Can someone explain the difference between superelevated & unbalanced? Thx.

 

[dlerach]

The two kind of add up to create the maximum speed that a train can traverse a curve.

Superelevation (also called Cant) refers to the banking of the track through a curve, which allows trains to traverse the curve at greater speed than if it were flat. Superelevation is measured in the inches that the outside rail sits above the inside rail on a curve. Most freight lines (I believe) superelevate up to 4". Amtrak definitely has some 6" curves, and I know that the PRR at times had 7" on the passenger tracks on a few curves between Harrisburg and Pittsburgh.

If a train goes the "correct" (perfectly balanced) speed through a superelevated curve, passengers will not feel that they are turning at all. Unbalanced superelevation (also called Cant Deficiency) begins when you exceed that "correct" speed. Unbalanced superelevation is measured in inches, as if the curve gained even more superelevation. So a train cleared to run with 5" of unbalanced superelevation can run through a 6" curve as if it were 11". For example, a train with 3" cant deficiency running through a 2° curve with 6" superelevation can go 80 mph, more or less. A train with 7" cant deficiency (the Acela) could take that same curve at 95 mph. If you added another inch of superelevation, the Acela could go 100 mph.

 

[GDRRiley]

Most freight lines (I believe) superelevate up to 4". Amtrak definitely has some 6" curves, and I know that the PRR at times had 7" on the passenger tracks on a few curves between Harrisburg and Pittsburgh.

yes 4 is the common limit for lines with tall freight.
there were some that pushed 8in

If a train goes the "correct" (perfectly balanced) speed through a superelevated curve, passengers will not feel that they are turning at all. Unbalanced superelevation (also called Cant Deficiency) begins when you exceed that "correct" speed. Unbalanced superelevation is measured in inches, as if the curve gained even more superelevation. So a train cleared to run with 5" of unbalanced superelevation can run through a 6" curve as if it were 11". For example, a train with 3" cant deficiency running through a 2° curve with 6" superelevation can go 80 mph, more or less. A train with 7" cant deficiency (the Acela) could take that same curve at 95 mph. If you added another inch of superelevation, the Acela could go 100 mph.

I will also add you typically want a minimum of 1in of unbalanced superelevation for stability.

 

[Bfputtzman]

has 213.57 been revised sense 2008? my data is all being pulled from CAHSR so if it has then it would make sense its a bit out of date.
tilting should allow you to push higher than 5in UB which means as usual the FRA was pretty conservative when it allowed only 5 on tilting trains

It was revised in 2013: Federal Register :: Request Access

yes 4 is the common limit for lines with tall freight.
there were some that pushed 8in

I will also add you typically want a minimum of 1in of unbalanced superelevation for stability.

Most freight lines actually limit super-elevation to 5-inches but have stated preference for not exceeding 4-inches. This is an excellent report summarizing methodologies, particularly pages 17 - 27: https://dotcms.fra.dot.gov/sites/fra.dot.gov/files/2019-12/Superelevation-Guidance_pdfa.pdf

What's not directly stated in the report is that most freight railroads limit super-elevation to essentially be flat (1/2" to 1-1/2") on mainlines in terminal areas as they don't want trains holding or running in/out of yards at low-speed over curves with 3" / 4" / 5" super-elevations. Similar comments for limiting super-elevation in the 3" range toward the tops of long grades where train speeds are slower than the "open running" norm. Being a freight-focused and freight-owned RR system in this country, these issues are at odds with consistent actual high-speed (Class 6+ / 95-mph+) running on a shared network and can generally only be achieved on a shared network where curves are of particularly low-degree (think 1-degree, 30-minutes at most) and/or where freight traffic is already running predominantly "fast" and will be operating within equilibrium at 5-inch super-elevation while the passenger train is operating considerably faster (leveraging 5-inch cant deficiency, the general upper bound for non-tilting equipment). There are plenty of example routes in the flat midwestern states where curvature is limited, and famous named trains operated fast in years past, for example, BNSF's Transcon in IL, MO, and KS where bilevel cars operate today over long stretches at 90-mph using a conservative 3-inch unbalance.

Back to the NEC, I slapped together the attached charts for perspective on maximum speeds by degree-of-curve based on 5-inch cant deficiency or 7-inch cant deficiency and current understanding of Amtrak's limits from the above report. Red shading indicates the curve-speed combination requires super-elevation beyond the 5.5-inch limit referenced, and Gray shading indicates the calculated value is negative or less than 0.5 and therefore requires Amtrak's 0.5-inch minimum super-elevation (again, from the above report). In other words, the Gray & White areas should be "in play" while the Red areas are off limits. This indicates 220-mph can only be achieved on curvature of 0-degrees, 20-minutes or less (which some railroads consider a line swing) and utilizing 4-3/8" super-elevation and tilt equipment leveraging 7-inch cant deficiency/unbalance.

Who knows where to find a track chart (aka track profile) for the NEC?

 

[jis]

The main problem on NEC for speeds significantly above 160mph even on straight track is the absurdly small track center distance that is the norm all along the corridor. And fixing that is a hugely expensive proposition that the Tier 1 EIS addresses in one of the so far rejected alternatives.

 

[Maverickstation]

Another factor with NEC Speeds are the sections of the road with high frequency services by the regional commuter providers.

On our last Acela trip from Boston to New York, we had some sections of high speed (over 110 mph) running south of Route 128, and then after Providence. Once in Connecticut the running was slow first along the Shore Line east segment owing to curves, and the various movable bridges.

Once we hit the Metro North service area, the running was slower "due to congestion", which makes sense given that although the route south, or east of New Haven, is 4 tracks, you have very frequent Metro North trains, both local and limiteds/expresses that operate 7 days per week.

Ken

 

[BlackDiamond]

Once we hit the Metro North service area, the running was slower "due to congestion", which makes sense given that although the route south, or east of New Haven, is 4 tracks, you have very frequent Metro North trains, both local and limiteds/expresses that operate 7 days per week.

From New Haven to Devon only 3 tracks as track 3 was removed many years ago. Also I'm many places due to ongoing renewal of infrastructure the line is effectively 3 or in some cases only 2 tracks.

 

[Maverickstation]

From New Haven to Devon only 3 tracks as track 3 was removed many years ago. Also I'm many places due to ongoing renewal of infrastructure the line is effectively 3 or in some cases only 2 tracks.

Plus, you still have about 11 Grade Crossings in Connecticut, which also limit speeds.

It would be curious to know that on the State Owned portions of the NEC such as the segments in
CT, and in Massachusetts (the Commonwealth owns the NEC), how are Amtrak services prioritized.

Ken

 

[jis]

Plus, you still have about 11 Grade Crossings in Connecticut, which also limit speeds.

It would be curious to know that on the State Owned portions of the NEC such as the segments in
CT, and in Massachusetts (the Commonwealth owns the NEC), how are Amtrak services prioritized.

Ken

The Massachusetts portion is operated and dispatched by Amtrak, so there should be no issues with Amtrak trains being treated properly.

In CT Amtrak operates and dispatches the portion from Mill River (just outside New Haven) to RI Border, so there should be no problem there either, The rest in CT is operated and dispatched by MNRR (CT border to Mill River (exclusive AFAIR)).