Acela Speeds

I was under the impression that 160 mph speeds were waiting on the FRA to permit them, as Class 8 Track permits 160, but for some reason Acela's HSR tier only permits 150

That is because they are working on Tier 3 train speeds etc. The Tier 2 trains were 125-150. Tier 1 high speed is anything under 125. These arent just made up tiers there are track safety, equipment maintenance and other requirements that must be followed to meet these tier specs and be able to operate in such a way.

As far as the acela times go the trains used to have a slight advantage before the 188 wreck and the cab drops were added for civil speed enforcement on curves without ACSES. They are slowly trying to work to bring those speeds up from 45mph to whatever is okay for the curve. Some have been removed all together in areas where ACSES is in full force and no non ACSES trains travel thru that poriton of railroad. But for example, the acela going thru Metuchen can only go 45mph around a curve it can normally do 95 and 110. The Acelas have extremely good brakes, so when they get the cab drop and have to suppress the trains drop right to that speed and have to travel it for a longer distance. The regional sets have ways of being "pushed" thru these sections at higher rates of speed and coming out the other side where it goes back up to normal at speeds better than the 45mph the acela has to do the whole way, and thats why a regionals time and acela are on the same spot. The acela and the new ACS accelerate at almost the same rate of speed, ACS64s are very powerful in boost mode. Hopefully with new trainsets they will be even more powerful and not as heavy.

The metuchen curves were just upgraded to a Cab 80 aspect that allows them to do 80mph thru, the one curve for regionals and NJT is 80mph as the lowest speed thru the area so they settled on that. Its not the 95 that the Acela can do, but its something.

Here's a shot of an Acela under constant tension catenary on track 4, and another of installation work on track 3 from last month:

https://www.instagram.com/p/BYhtZDnFOtd" onclick="window.open(this.href);return false;

https://www.instagram.com/p/BYgidUhlZWJ" onclick="window.open(this.href);return false;

Well, even if the constant tension stretch was scaled back, there's definitely less catenary movement with the upgraded variable tension hangars.

https://www.youtube.com/watch?v=xavCP4rCN3A" onclick="window.open(this.href);return false;

it does still move with those hangers, the spot you are in there they are hanging from a solid beam. The ones that still use wire for the cross sections do still move a bit, but one track does not affect the others as much. The biggest issue is that a train moving quickly on one track can actually make the wire on the track next to it bounce even worse than the track the high speed train went down. The new hangers cut that down quite a bit. I have studied it while working out at Adams yard. I am hoping with the new hangers they can at least get to 140 maybe 150 without the CT for now. They still need to do new high speed testing again with the high speed test cars and cameras to see how the wire reacts.

Always wondered why they didn't go to a center pole setup when they electrified the New Haven to Boston section of the NEC. One of the most controversial aspects of the project was the aesthetics of the poles and overhead wires. Going to a center pole would have eliminated half of the poles.

Wouldn't construction of half of the poles greatly reduce construction time and expense? Also, wouldn't this setup eliminate any problems of high-speed trains on one track effecting the overhead wires on adjacent tracks? Wouldn't this set up create better separation of track centers benefiting high-speed rail in general?

Just thinking out loud here, but this is from the California High-Speed Rail study:

Poles have many advantages:

Poles and brackets are easier to maintain without affecting multiple tracks

Poles and brackets are mechanically robust to pantograph failures containing damage to the affected track

Poles are much lower than headspans (32 ft above rail versus 43 ft, according to Caltrain engineering drawings) and therefore less visually obtrusive

Poles keep high voltage away from the edges of the right of way, where they might interfere with surrounding objects and vegetation. The 50kV feeders are now hung above the tracks . . . a 4-foot voltage keep-out zone is smaller and concentrated over the tracks unlike headspans.

For either poles or headspans, the four-track electrified right of way running at ground level can fit within 70 feet. (NOTE: this would be a four track ROW with single poles between the outer and inner tracks)

Does it have something to do with snow that California's catenary poles will more-or-less never be burdened with outside of maybe a the occasional dusting up Tehachapi or through the High Desert?

A report I read indicates that service wont start under the new speeds until 2019 at the earliest with 2020 looking more like it... 3 years behind schedule !

Not totally surprised, though you'd think once the constant tension wires are in place (looks like they're done with tracks 3&4 and are currently working on track 2 through Princeton Junction) it'd be a trivial matter to bump the Acela from 135 up to 150, even if 160 mph will have to wait for the Avelia trainsets.

bdawe wrote:Does it have something to do with snow that California's catenary poles will more-or-less never be burdened with outside of maybe a the occasional dusting up Tehachapi or through the High Desert?

Probably not but remember the Santa Anna and Chinook winds.

bostontrainguy wrote:Always wondered why they didn't go to a center pole setup when they electrified the New Haven to Boston section of the NEC. One of the most controversial aspects of the project was the aesthetics of the poles and overhead wires. Going to a center pole would have eliminated half of the poles.
...

Two reasons: First - The New Haven - Boston electrification was retrofitted onto an existing, active passenger railroad. Constructing a system with only a single support located between the tracks would have required both tracks to be taken out of service for foundation installation - about 40 or more a mile. That would have severely limited the track time availability for construction and would have extended construction time. With supports on both sides, only a single track needs to be taken out of service at any given time.

Second, the existing track centers would not have have provided modern code clearance to the support columns. A system built from scratch can set tracks far enough apart to allow support columns between the tracks within current code, but with an existing railroad the geometry is what it is, and in this case, it was not enough.

prr60 wrote: Two reasons: First - The New Haven - Boston electrification was retrofitted onto an existing, active passenger railroad. Constructing a system with only a single support located between the tracks would have required both tracks to be taken out of service for foundation installation - about 40 or more a mile. That would have severely limited the track time availability for construction and would have extended construction time. With supports on both sides, only a single track needs to be taken out of service at any given time.

Second, the existing track centers would not have have provided modern code clearance to the support columns. A system built from scratch can set tracks far enough apart to allow support columns between the tracks within current code, but with an existing railroad the geometry is what it is, and in this case, it was not enough.

Your first two answers were very good, but you missed maybe a third more important reason, it was cheaper.
Engineers, congressmen, businessmen, and consumers will usually choose the cheapest acceptable solution to any problem.
It doesn’t matter if you are using a car, truck, train, or plane; you are riding in the cheapest solution using the cheapest materials by the cheapest manufacturer using the cheapest labor.

Interestingly, I just found this video of a "reverse" cab ride on the NEC through Rhode Island. Surprisingly, most of the catenary is on a single pole! At first I thought it might be because of the third track in some areas, but it seems like it is predominate on this stretch.

Possibly something to do with doublestack container territory? I don't know.

So would this have been cheaper to implement over most of the entire route?

https://www.youtube.com/watch?v=iOSFzZgNhrM" onclick="window.open(this.href);return false;

prr60 wrote:

bostontrainguy wrote:Always wondered why they didn't go to a center pole setup when they electrified the New Haven to Boston section of the NEC. One of the most controversial aspects of the project was the aesthetics of the poles and overhead wires. Going to a center pole would have eliminated half of the poles.
...

Two reasons: First - The New Haven - Boston electrification was retrofitted onto an existing, active passenger railroad. Constructing a system with only a single support located between the tracks would have required both tracks to be taken out of service for foundation installation - about 40 or more a mile. That would have severely limited the track time availability for construction and would have extended construction time. With supports on both sides, only a single track needs to be taken out of service at any given time.

Second, the existing track centers would not have have provided modern code clearance to the support columns. A system built from scratch can set tracks far enough apart to allow support columns between the tracks within current code, but with an existing railroad the geometry is what it is, and in this case, it was not enough.

With the NJ portion, it is not about cheaper. The ROW is listed on the National Historic something the other registry, so i believe it was part of the requirement that the replacement poles had to pretty much resemble the ones removed/were of PRR design. Plus as it is right now its beyond a cluster f!@# just to put up the poles and wires they are doing as we speak dealing with the current train traffic. Forget trying to move the track centers!

ApproachMedium wrote:Forget trying to move the track centers!

Wasn't that part of the original plan though?