• SEHSR Southeast High Speed Rail Corridor

  • General discussion of passenger rail proposals and systems not otherwise covered in the specific forums in this category, including high speed rail.
General discussion of passenger rail proposals and systems not otherwise covered in the specific forums in this category, including high speed rail.

Moderators: mtuandrew, gprimr1

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  by Chafford1
 
villager wrote: I think the GNER in Britain is a fossil-fuel powered train that can do 143 mph, but it probably pulls much lighter coaches than FRA-compliant equipment, which of course means you have to build it like a tank.
You're describing the diesel High Speed Trains in operation since the late 70s. They run at up to 125mph on the East Coast and other lines in the UK.

  by george matthews
 
Chafford1 wrote:
villager wrote: I think the GNER in Britain is a fossil-fuel powered train that can do 143 mph, but it probably pulls much lighter coaches than FRA-compliant equipment, which of course means you have to build it like a tank.
You're describing the diesel High Speed Trains in operation since the late 70s. They run at up to 125mph on the East Coast and other lines in the UK.
Um. A few of the East Coast trains are diesel. Most are electric. BR Mark 4 were designed to do more than 125 but the track has never been improved enough.

  by RVRR 15
 
Chafford1 wrote:
villager wrote:
Chafford1 wrote: That's a very high average speed for a line with a maximum 110mph!
The amount of straightening of curves is really the key here. This line is defunct for much of its length, so there is an opportunity to rebuild it as if it were "done right the first time."

To see the type of relocations we are talking about, take a look at the blue line proposed on this satellite photo.
Dead straight! If this is a new line they should go for a higher maximum speed than 110mph.
If they're going to maintain tracks to Class 7 specifications, the FRA is not going to permit any faster than 125 mph. Such a speed is actually old-school; some first-generation diesels, like the Alco DL-109 and early E-units, were geared for at least 120 mph. With single units having double the horsepower of these early machines, a re-gear (or re-certification) would be prudent.
villager wrote:I certainly agree, though I don't know what's out there in terms of non-electric propulsion to pull trains at speeds above 110. This line is not planned to be electrified when it opens.

It would be great if there was some fossil-fuel powered loco that could get up to 125 on the straighter sections. I think the GNER in Britain is a fossil-fuel powered train that can do 143 mph, but it probably pulls much lighter coaches than FRA-compliant equipment, which of course means you have to build it like a tank.
Trains on the former LNER, as noted, are electric. The Class 91 was supposed to be running at 140 mph in daily service, but the government cut off funding and the top speed is currently 125 mph.

The British Rail Class 43 is the original diesel "HST" (built between 1976 and 1982), with top speed in revenue service of 125 mph; in tests, it has allegedly gotten up to 148 mph (two units, 2250 horsepower each). US passenger diesels could easily perform at this level (or outpeform, possibly; they could out-accelerate, certainly), if geared correctly; however, the FRA would insist on appropriate signaling and Class 8 track for daily operation of this kind.

  by villager
 
RVRR wrote: If they're going to maintain tracks to Class 7 specifications, the FRA is not going to permit any faster than 125 mph. Such a speed is actually old-school; some first-generation diesels, like the Alco DL-109 and early E-units, were geared for at least 120 mph. With single units having double the horsepower of these early machines, a re-gear (or re-certification) would be prudent.
I know nothing about gearing. Can you tell us more about how re-gearing raises speed? For example, the Wikipedia page on the F59-PHI says it has a max speed of 110 mph and a gear ratio of 56:21.

Thanks for those who corrected my comments about the english HSTs.

  by David Benton
 
the english hst gets up and goes . I dont think a heavy american trainset could out acclerate it . What makes you think they could ???

  by george matthews
 
David Benton wrote:the english hst gets up and goes . I dont think a heavy american trainset could out acclerate it . What makes you think they could ???
I rode in an Oz XPT which seemed to based on the HST. About 20 years ago. Do they still have them? It was from Grafton to Sydney.

  by David Benton
 
yes george they do . that was my first 100mph train ride ever ! .
I rode one of them a couple of years ago from sidney to Brisbane . theyve got them on quite a intensive schedule . they have different susppension form the english hst's to cope with the "colonial trackwork" .

  by RVRR 15
 
David Benton wrote:the english hst gets up and goes . I dont think a heavy american trainset could out acclerate it . What makes you think they could ???
Acceleration and top speed are not limited by weight; they are limited by power-to-weight ratio. US trains have quite a bit of muscle (consider the InterCity 125's starting TE of 17980 pounds for a single power car versus the 58000 pounds of the F40PH, just for one example; later locomotives have starting TE way higher than that, approaching the 70000-lb mark; and if you add higher horsepower and AC traction motors on top of that, your potential top speed can be quite high).

As for pure weight, a nine-car Intercity 125 would be up in the range of 1,116,400 pounds empty, so if you compare it to the "overweight" Acela Express expanded to a nine-passenger-car formation (at 1,665,000 pounds), i.e. to even the seating (although a nine-car AE would have 27 more seats than a nine-care HST), the HST's 8.06 horsepower per ton compared to the AE's 14.41 horses per ton still seems a bit anemic. (Remember; the USA still has diesels out there that can easily match the HP/ton ratio of the AE.)

  by David Benton
 
The acela is electric .
are you allowing for the wieght o fthe engines as well ???

  by RVRR 15
 
These are whole trains I am citing. Tier 1 passenger cars would weigh less than the Acela Express' passenger cars. Acela Express power cars are 204,000 pounds each; newer passenger B-B diesels are in the 290,000+ pound range.

BTW, two P42DCs with nine Amfleet IIs would give you a power to weight ratio of 10.65 horsepower per ton. Replace those with two 6,000-horsepower diesels and you are up to 15.21 horses per ton.

  by Nasadowsk
 
RVRR 15 wrote:These are whole trains I am citing. Tier 1 passenger cars would weigh less than the Acela Express' passenger cars. Acela Express power cars are 204,000 pounds each; newer passenger B-B diesels are in the 290,000+ pound range.

BTW, two P42DCs with nine Amfleet IIs would give you a power to weight ratio of 10.65 horsepower per ton. Replace those with two 6,000-horsepower diesels and you are up to 15.21 horses per ton.
Nobody in the US makes (or ever made) a 6000hp diesel. The HP ratings of diesels in the US are prime mover ratings, what actually hits the rails is considerably less, about 20% less. Then you add HEP losses on top of that, and you're looking at even less power - a P-42 loses about 600HP to HEP, then has generation/transmission loses. They really are only 2900hp or so units. If you look at the TE:Speed curves of any US diesel, you'll find they just don't have much oomph at all - according to NJT's TE curves, an Arrow III pair actually has as much power as a PL-42 at about 50mph, and the considerably lighter (90,000 lbs!) ALP-46 actually out powers a '42 at all times - even starting. In fact, due to the slow onset of power in US prime movers (due to high rotating mass and a slow, single turbocharger), the acceleration is even more pathetic - they litterally can't get up to full power quickly - an '46 can go from 0% to 100% in three seconds, a PL-42 takes <b>twenty</b> to do the same thing.

US diesels aren't suited at all for high speed passenger service. They're good for dragging coal around at 20mph. That's why you see few, if any, GM and GE locomotives used overseas for passenger trains - what places aren't electric use the much better suited locomotives based on high speed diesel engines.

  by RVRR 15
 
Nobody in the US makes (or ever made) a 6000hp diesel. The HP ratings of diesels in the US are prime mover ratings, what actually hits the rails is considerably less, about 20% less. Then you add HEP losses on top of that, and you're looking at even less power - a P-42 loses about 600HP to HEP, then has generation/transmission loses
Putting the cart before the horse, are we? I never claimed that the USA has ever made a 6000-horsepower passenger diesel—I said that it was possible. Doesn't suit your argument to put words in people's mouths.

I noticed you left out a part of the Genesis locomotive name, that being the P42DC. AC traction motors have contributed greatly to higher wheel horsepower. (Note the AC6000, on the freight side of things.)
If you look at the TE:Speed curves of any US diesel, you'll find they just don't have much oomph at all - according to NJT's TE curves, an Arrow III pair actually has as much power as a PL-42 at about 50mph, and the considerably lighter (90,000 lbs!) ALP-46 actually out powers a '42 at all times - even starting. In fact, due to the slow onset of power in US prime movers (due to high rotating mass and a slow, single turbocharger), the acceleration is even more pathetic - they litterally can't get up to full power quickly - an '46 can go from 0% to 100% in three seconds, a PL-42 takes twenty to do the same thing
You're comparing apples with oranges.

And I see that you cite no other diesels to compare with US diesels.

What's more, you're looking at a single unit versus multiple locomotives.

Not to mention, you are not citing alternate (higher) gearing, and focusing on the status quo. (Did you forget that the P42DC operates on the Northeast Corridor in revenue service?)
US diesels aren't suited at all for high speed passenger service. They're good for dragging coal around at 20mph. That's why you see few, if any, GM and GE locomotives used overseas for passenger trains - what places aren't electric use the much better suited locomotives based on high speed diesel engines
You are omitting facts. All of the EMD and GE diesels sold for export of late have been drag freight types, and there are no passenger diesels in the catalog. The countries that buy such freight diesels usually operate DMUs on non-electrified lines.

Furthermore, you are not clarifying what you mean by "high-speed passenger service". Without giving us a benchmark, you are speaking into the air.

  by David Benton
 
the hst power cars are 70 tonne each . thats 154 000 pounds each , so 308 000 tinnes for the 2 . 9 cars at say 20 tonne each , 180 tonne equals 396 00 pounds . so around 700 000 pounds for the hst trainset . i make that 14 hp per tonne . dont forget this is 25 year old technology , the hsts were replaced by pendinlino trainsets to achieve better power to weight ratios , and hence accleration .

  by RVRR 15
 
44000 pounds sounds very light for a BREL Mark 3.

Since the West Coast Main Line is electrified, how could Virgin's Pendolinos replace the InterCity 125?

  by Nasadowsk
 
RVRR 15 wrote:
I noticed you left out a part of the Genesis locomotive name, that being the P42DC. AC traction motors have contributed greatly to higher wheel horsepower. (Note the AC6000, on the freight side of things.)
AC or DC motors makes no difference on the horsepower. Sure, it might mean a different torque curve, but there have been plenty of high HP DC motors out there, along with plenty of high HP AC ones. A 100 HP electric motor is 100HP, regardless of it being DC, AC, wound rotor, synchronous, asynchronous, series wound, shunt, repulsion, etc. It's 100HP, period.

Ok, one place where AC does make a difference - on a diesel locomotive, you now have to add your inversion losses to the transmission losses. DC's actually very slightly more efficient, but AC allows far better control, so you get better overall TE.

BTW, DB's class 103 locomotives of the late 60's had a short time rating of 10,000 HP, and were DC machines (thyristo rectifers, though they were tap changer units, as phase angle control at that time couldn't meet DB's requirements).

And in any case, i was comparing NJT's <b>PL</b>-42 to their ALP-46. The PL-42's an AC unit with an EMD prime mover. I'd expect a GE powered unit to be even slower, since GEs take forever and a day to load, for some reason known only to GE...
Not to mention, you are not citing alternate (higher) gearing, and focusing on the status quo. (Did you forget that the P42DC operates on the Northeast Corridor in revenue service?)
Gearing means virtually nothing on AC units. With IGBT inverters and today's more advanced controls, the difference in TE between a 125mph locomotive and a 100mph one is trivial (if it even exists). Besides, the actual HP delivered at the rails by any of the current US passenger diesels is so low, that it's not even worth bothering to achieve higher speeds, especially with the overweight trains this country runs. Amtrak's '110mph' track in NY state is a cute thing, but the reality is that with any train longer than a 4 or 5 cars, the train spends so little time at 110mph, it's not even worth it. Even the Acela's much flaunted 150mph running is so insignificant in the grand scheme of things, that it shaves barely a minute off the schedule over 125mph running.
You are omitting facts. All of the EMD and GE diesels sold for export of late have been drag freight types, and there are no passenger diesels in the catalog.
Of course they're drag units. They're unsuited for passenger service. Today's modern passenger operations demand accelerations far higher than US equipment can achieve, period.
The countries that buy such freight diesels usually operate DMUs on non-electrified lines.
Of course they do. They don't want their lines clogged up by passenger trains that can't get out of their own way. And since most diesel lines are feeders to larger mainlines (inevitably electric), they need to be small trains, and they need to have electric-compatible performance. At one time in the last few years, the fastest multiple unit out there was, in fact, a diesel. Modern DMUs such at the Stadler GTWs, offer performance that can't be touched by a locomotive hauled train, with a far lower noise and emissions footprint. Of course, EMUs today are a bit faster, as power electronics have gotten better/lighter/smaller/more powerful - Stadler's FLIRT can go from a standstill to 90mph - in under a minute.
Furthermore, you are not clarifying what you mean by "high-speed passenger service". Without giving us a benchmark, you are speaking into the air.
Last I checked, the UIC standard was 125mph (220km/h) and up. Only the FRA thinks going faster than 80mph (140km/h) is 'high speed', nobody else does.
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