I was wondering if I could get your opinion on if Amtrak and Via would do well to use trains that tilt on the corner. Since the APT in Great Britain which was a great short term success, Alstom has come up with the Pendolino and is used by Virgin in Great Britain. It is becoming popular because it means that it can go quite fast but doesn’t have to have its own line because it can turn on the sharp curves without derailing.
I know that the FRA likely does not permit the Pendolino yet but would tilting trains do well in North America?
The X2000 was a tilting Sweedi***rain that barnstormed America back in 1999-2000. It was supposed to go faster on the curves. You look at Swede track & American track and see the same thing. A F40 could pull the thing in non-electric territory. It most likely would work fine in the 600 mile midwest corridors (St Louis- Chicago - Detroit) etc. Therhas been some work for improved track & better crossing protection on these lines. Mostly these are state projects with state DOT money.
…I only know what I read about Talgo…is it still being used on the west coast…? And yes it has tilting ability, but wheither that feature is being used…another question. From what I read they were run under speed restriction…Does anyone know the present setup of what is being done with them now…?
jruppert, you’re right, the Cascade (and the Las Vegas service) are tilting trains. Like the old United Aircraft TurboTrains, they use “pendulous banking” to implement the necessary ‘negative cant deficiency’ corrections; the Talgo Pendular can also use powered control if desired to control the degree of tilt.
Talgo, Inc., a Washington State corporation, which is responsible for the Cascade trainsets, is a wholly owned subsidiary of Patentes Talgo of Madrid, Spain. In 1998, a press release indicated “For more information, contact Talgo COO, Jean-Pierre Ruiz at (206) 748-6140” – this number may still be good, and I’m quite sure they’d be interested in addressing SENSIBLE (hint, hint, hint) and relevant questions regarding suitability of these and other Talgo trains for various routes, as well as ways that freight trackage could be optimized to permit relatively high passenger running speeds while not compromising wear and safety issues for other types of train movements.
Here’s a link that may make the approval issue a bit clearer to you regarding why these trains qualify to operate in the United States while Pendolinos may not:
A significant piece of this approval appears to be tied in with the use of those ‘dead’ F40 control cars on the opposite ends of the early trains (I saw one of the early sets in action in Seattle in the mid-90s, before the cabs were used, and would not have wanted to be in the rear of that train during a collision with a following locomotive!) It is possible that a Pendolino with comparably-structured end units might achieve at least a developmental waiver from FRA – this was obviously not a practical option for the Colorado Railcar DMU.
The place to start when researching this sort of thing is probably
…Yes, the zone in the Mercedes where she was occupying was pretty much intact and if she would have been restrained she could have prevented being a flying projectile…
In my country ve haff a sayink; “Your right to speed is your ability to stop”. What this means is that you can only go faster if you can bring the train to a stand within the same distance as a slower train, or you have to lengthen the blocks so the faster train can stop between the yellow signal and the next one at red. You can’t just put in more brakes becasue you are limited by the friction between the wheel and rail, and longer blocks means reduced capacity in terms of trains per hour.
MODERN rail systems don’t use blocks; they use continuous signaling and PTC. An example of this is the Sandia AATC project, which could be rather easily adapted to high-speed mainline use via much of the same infrastructure used for NDGPS.
Braking hasn’t been limited ‘by the friction between the wheel and rail’ for a very long time – various flavors of electromagnetic track brake, for example, have been around for decades. These have limits too, of course, one of them being the eddy-current heat rise in the railhead, but they are assuredly capable of stopping trains very, very quickly without impairing the wheels or suspension of a high-speed train. Indeed, the deceleration rate becomes limited by passenger discomfort, or outright injury, unless passengers are restricted to their seats and well-secured by belts and other restraints or harnesses at the time ‘emergency’ braking of this class is applied.
Of course, this doesn’t take away one whit from the point Hugh is making, even if it is somewhat ironic coming from the land of the vacuum brake and crockery-smashing transits of Crewe. No discussion of high speed should be conducted without ensuring that the faster trains can’t be stopped where and when needed, without fuss or incident, even under inclement weather conditions (etc.) SAFELY for all concerned. All the fancy algorithms and superconducting magnets in the world won’t replace common sense, due caution, and knowledgeable engine crews…
The newest TALGO-trains - “Donald Duck trains” - are designed to run at 350 km/h top speed. There are no restraints in European high-speed-trains. Considering the small probability of an accidet, I don’t believe they are necessary. I have never heard of restraints on Japanes high speed trains, and they are very safe too. (due to gauge difference, they have their own right of way, but they use the same stations as cape-gauge trains.)
tilt trains do not necessarily operate on decicated high speed right of way. they are often intended to increas speed on conventional lines. the combination of tilt train and high speed train is of course possible. it all depends of the needs of the market and the money available.
Of course, European high speed trains reach their top speed only on dedicated right of way where no freight trains are running on the same line - at least not at daytime.
I habe never heard that people near a high speed track have caused danger in Europe. Especially France has several high speed tracks and therefore ample experience as to safety problems.
Martin, I don’t think we’ll ever really see proper restraints in high-speed trains – we don’t even see them in airplanes! Many people who ride Amtrak in the NEC would probably be irritated merely by a seatbelt requirement. I would be among them.
On the other hand, in the United States the legal situation after an accident may be ‘worse’ regarding liability for the kinds of physiological damage likely to result from high speed. Not my argument, but plaintiffs’ attorneys.
I concur that the principal use of tilting trains is for conventional rights of way – that was the gist of Junctionfan’s original question (here and in the GL&A thread) regarding the Pendolino et al. He only extended it to TGV as an afterthought, which is why I tried to divide the issue somewhat.
The Talgo 350 and Nozomi trains are interesting. Imho you’re completely right about market needs and money (although I might reverse the relative order!) I’m not sure there are too many places in the United States (outside the usual NEC regions) where the capability of these trains would be needed – as of April 2004 even 110mph passenger corridors are in some doubt. Hopefully that will change…
I was concerned with people near lineside who would be at risk of being involved in a high-speed accident, not so much with trespassers, would-be vandals, etc. etc. The new lines in France IIRC were sited and oriented to minimize this issue. (I would think that the NIMBY noise problem would be more important to ‘neighbors’ than any perception of derailment risk!)
What can people tell me about the Pennsy Keystone train? On another thread on this forum, someone fessed up to riding it out of Metropark. It was very low to the ground – the late David P Morgan had a photo in Trains titled “Oo la la!” about how with the train in Penn Station, he was tempted to look up women’s dresses on the high level platform, which was at window height.
Did the Keystone tilt? You would think that the point of making the train that low to the ground was to allow it to tilt using a high roll center – active tilting trains can have a low roll center and don’t need such exotic construction.
As to the Talgo and the passive pendulum tilt, their system takes out only roughly half the lateral acceleration – part of this is limitations of pendulum tilt, limitations of their design, and a desire that passengers feel some lateral forces so they don’t get sick from the train banking without feeling the forces (that is part of why airline passengers start barfing in a holding pattern).
Lets say you have 3 degrees of superelevation, you allow the passengers to feel 3 degrees worth of off-the-vertical force, and the Talgo tilts 3 degrees (the Talgo compensates half the uncompensated-by-superelevation forces – I am guessing, it could be only a third). The Talgo allows a total 9 degrees of effective tilt (1.5 m/s lateral acceleration) while a non-Talgo allows only 6 degrees of tilt (3 degrees of superelevation plus 3 degrees worth of passengers pushed sideways for a total of 1 m/s lateral acceleration). The Talgo allows 50 percent more lateral force, but since acceleration is v squared over curve radius, the Talgo is allowed to go about 22 percent faster in curves.
I saw some charts on Talgo Cascades, and I believe they were allowing Talgo only 12 percent faster, but I saw a photo on the Web of a curve speed restriction sign that was closer to 22 percent. The point is that with passive tilt you don’t go a lot faster around curves hence the interest
I sort of disagree, as far as I am aware PTC is still a rare thing on the railroads, apart from the example you mention name 20 or 30 more and I might be convinced… I couldn’t find a figure on the percentage of route miles that is currently controlled using PTC, but I would be very surprised if it was more than 1%. All I could find was talk of pilot schemes and evaluation trials. Continuous signalling does not necessarily mean PTC is being used, the TVM430 signalling used on the TGV network is still based around blocks and track circuits.
Of course there are eddy current, and friction track brakes used, but these tend to come into play only during emergency applications. Good old fashioned friction brakes, albeit disk, are still the norm for service brake applications, at least that’s the way it is round my neck of the woods.
I didn’t mean to imply that there ARE lots of PTC applications deployed, only that they’ve already demonstrated to my satisfaction (which is NOT an easily-obtained satisfaction!) that they work as well or better than formal block systems, and that their technology can be adapted to flexible-length block systems that do not have the inherent problems with block length optimization that you quite correctly brought up.
BTW, I am not at all confident that the NAJPTC system is at all a suitable object model for real railroading – it’s brittle, uses central servers for important functionality, and has already demonstrated typical programmer errors (my favorite so far being that some trains have zero length – they enter one block and clear another at the same time.) In my opinion, a proper PTC design should have some expert-system software enablement, and use nondeterministic logic in much of its ‘case assembly’. Current systems aren’t quite ready for prime time, and considering what it will cost to implement some of them, it’s well worth waiting until the program code is certifiably showstopper-free (or the code programmers are certifiable…)
Some people define PTC as continuous signalling plus ATC functionality – it not only advises the engine crew of signal indications, it backstops them with proportional or absolute braking if they miss something. I have never particularly liked ATC systems that pull the air on the engineer, no matter how “necessary” that may be: imnsho, a ‘proper’ PTC system is like one-half a full automatic or remote system in that it will proportionally modulate braking and throttle to slow the train as needed to maintain minimum safe distance. Even with a compromised consist, wet rail, or unexpected brake-system failures.
My understanding was that modern eddy-current track brakes were more useful in reduction from high speed/high kinetic-energy ranges down to the point where friction braking becomes more cost-effective – in other words, doing what
A little addition since my e-mail system has come back up this morning:
Notes from the APT group
Tilting trains tilt to maintain
passenger comfort whilst cornering at high than normal speeds, and
obviously the higher speeds require greater braking effort. But this is not new. Each time railway speeds have increased, newer better brakes have been required. Both APT-E and APT-P increased railway speeds significantly and thus required a newer better brake, and unsurprisingly both suffered a degree of brake problems, but that
was over 20 years ago.
I am very surprised that with today’s computers, with past
experience and knowledge, and the fact that the Virgin Pendolinos are not new
technology nor do they significantly increase railway speeds, that locking brakes are still a problem.
I get the feeling that in the coming weeks we will see a picture of a Pendolino with a tilt failure.
Uh oh ˆ I think I’m starting to sound like the press…
Alan,
Kit Spackman replied:
The problem may lie in the UK’s archaic track and signal infrastructure.
We’re still living with very short sections between signals, comparatively
speaking, which require the trains to stop very quickly. Of course the
ultimate limiting factor is still the steel wheel on steel rails, not
exactly the highest friction match on the planet. The combination of the
two results in almost impossible demands on the brakes.
At one stage APT-P was planned to use ‘double block’ working, needing twice
the distance to stop in, but that required in-cab signalling which never
got off the ground properly. Why that isn’t used now I’ve no idea, it
should be a doddle with todays technology.
If they can put down umpteen transponders to tell the train when to tilt
and when not to I’d have thought that additional ones to tell it to stop or
not stop wouldn’t be t
The PRR Keystone didn’t tilt, but ATSF had at least one tilting car built around 1940, called a “pendulum car”. It had very curved sides to allow tilting without exceeding the structure gauge. It was painted two tone blue and silver to match 4-6-4 3460. There was a similar prototype of a pair of articulated cars, one an observation built earlier, but this might not have been sold. These may have been the first tilting trains in the world.
Overmod, I know people at the Central Rivers depot where they maintain the Voyagers, I’ll see if I can get any info on any wheel flat problems thay may be having. They’s (Voyagers and Pedelinos) both fitted with the same wheel slide protection equipment.
As these trains have only just started revenue service usung tilt, all eyes are on the reliability of the tilting mechanism. But lilke you said, the technology isn’t new, so it might not be that bad.
In the end they added a flashing green aspect to the signalling system to give the train the extra stopping distance it needed, but it was all decommisioned once the APT was dropped.
They could easily do all the things you mention, but they’re too cheap to spend the money.
My view of the APT is that it was the Edsel of trains, just too advanced for it’s time. And when it was dropped all development of any of the technology used on it was dropped as well. The only thing used was the bodyshell, which went on to become the Mk.IVs.
If you worked on the APT hydraulics you probably know a lot of the same people I do. Small world innit…