Hello all ;
Here's a video depicting a high speed running in Europe. It's probably not new to most of you, and back here in a short time conventional trains just like these running at high speed will increasingly became a rarity, with all the high speed 'TGV' type lines being built and/or projected. Here's the video. Enjoy
http://www.youtube.com/watch?v=_Z27UFQ3Afs
I think we might need to point out that lots of track in the US already supports 100-mph running, but it's the signalling that is crippling it to 79 mph. This month's "Ask Trains" treats this problem in some detail. Sometimes the signalling costs as much, or more, than the track does.
Wow! I wonder how fast we were going? It is most impressive that in 6 minutes and 10 seconds we meet three other passenger trains and go through 6 stations, all modern and some in a rural area. There seemed to be an adjacent track on the left at a lower elevation during the second half of the video. Could that be an old main line or an industrial track? It seemed to be electrified.
I think this could be in Portugal. The "wrong line/direction" signal backgrounds had a rectangular background while the "right line/direction" signals had an oval background. This is characteristic of signaling in Portugal. Also, the YouTube channel is maintained by someone from Portugal.
High-speed trains like that in Europe usually do not have wayside signals. That's probably why we don't see that many.
Over the movie, track speed varies between 112 and 125 mph.
The Adjacent track (there used to be two, and yes it's the old main line) is a sort of long (7 miles in lenght) siding, with some suprs connected. It is normally used by frreights and it's limited to 37 mph. It is electrified since it's quite frequent to sideline mainline freights over there in order to let the faster passenger trains running smoothly.
Indeed it is, in the North main line some 30 miles from Lisbon (the train is running southbound).
About the 'wrong line/direction', I must state that there isn't a normal circulation way, since tracks are banalised. There are howevrer some limitations involved if, for istance, a train will have to be routed in the 'abnormal' way, such as as speed limit of 100 mph.
Also in the 'normally used' line - the one at the left, signal blocks are much shorter.
To be true, the train that we see doesn't need to rely on the wayside signals, since it's ATP equipped. However, there are still some trains - freighters - in wich the engines are not qequipped with it, hence the wayside signals.
The ATP is used in such a mandatory way, that if for some reason a faster train gets its ATP device out of order, a speed restriction os 100 kmhr (62 mph) will be de rigeur. Logicaly, in the lines with ATP, there are no speedboards indicating speeds higher that that.
For what it's worth, in the Northeast Corridor, Commuter Rail is mixed with Amtrak HST trains.
Often, while riding a north bound MBTA Commuter Rail at 80 mph between Providence and Boston, a double track line, the dispatcher will "fleet" the south bound track for Amtrak northbound service. The dispatcher radios the our train that we will be overtaken by train # *** about at MP **** .
We're moving north at 80 when an Acela "booms" by us in the same direction on the next track at 150. A real "waker upper".
Don U. TCA 73-5735
Ahh! I didn't think of the conventional trains using the European line. Of course they use the wayside signals, silly me.
When i've been on-board, they always called it in (this was several years ago)(security is much tighter now even tho I had gone through there safety training). You know, don't hang your head out the left side of the train to look.
Cab Signal Overspeed control is a regulation problem easily solved with money. The real key to high speed on existing rail lies in minimizing unsprung weight which in turn reduces Vertical Dynamic (P2)Track Forces. These are deep disturbances in the substrate that literally distroy the tracks. All European motive power has been designed to Pe Forces for years. None of Amtrak's locomotives, with their axle mounted motors, come anywhere close to being suitable for speeds above 79 mph. The exceptions are the Acela and the Turboliner Trains.(No longer in service). Much has been written on the subject going back as far as 1973. In 1993, Gordon Campbell and I presented a paper to the Transportation Research Board Committee on Intercirty Passenger Transportation titled, "High Speed on Existing Rights of Way, The Significance of Vertical Dynamic (P2) Forces". Body-mounted motors are best followed by truck mounted. The Acela has truck mounting and the Turboliners,with hydraulic drive, have only the partial weight of the cardan shafts and the axle gear boxes..
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aegrotatio I think we might need to point out that lots of track in the US already supports 100-mph running, but it's the signalling that is crippling it to 79 mph. This month's "Ask Trains" treats this problem in some detail. Sometimes the signalling costs as much, or more, than the track does.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Jerry PierBody-mounted motors are best followed by truck mounted. The Acela has truck mounting and the Turboliners,with hydraulic drive, have only the partial weight of the cardan shafts and the axle gear boxes..
Reaching back 15 years, Metroliner Service pulled by AEM7 locomotives cruised at 125 mph. I've been onboard when a Metroliner streached out to 129 mph (fudge factor). 10 years ago, with track work complete between New Haven and Boston, but without the Catenary ready, F40PH diesels were geared for and ran at 110 mph.
oltmanndJerry PierBody-mounted motors are best followed by truck mounted. The Acela has truck mounting and the Turboliners,with hydraulic drive, have only the partial weight of the cardan shafts and the axle gear boxes.. Does truck mounted include any differentiation between axle hung (nose suspended) and not? If I remember right, the AEM-7s have frame mounted motors that are not nose suspended. I would think this would be almost as good at body mounted - having the motors between the primary and secondary suspension.
The fellow in the office next to mine is doing his PhD research on some manner of electric drives. His "day job" has been with United Technologies Hamilton Sunstrand where electric drives are supposed to be eliminating all of the costly and maintenance-intensive hydraulic motors on airplanes.
I was giving him a hard time the other day, for all of the advances in motor design and the use of electronics to provide variable-speed control of AC motors, there is renewed interest in some form of flexible mechanical drive to get between the motor shaft and wheels of high-speed trains on account of the unsprung mass hammer-blow problem. He was "pulling my chain" for my interest in constant-velocity couplings, saying that if the power transmitted by high tension power lines were done with mechanical shafts, the shafts would have to be bigger in diameter than barrels. Of course one would not contemplate anything but electric transmission to get power from one geographic area to the next, but mechanical transmission appears to not be going away anytime soon, even people thought it would, for transmission over varying distances of feet or even inches in rail and automotive suspension.
Your traditional solid-axle rear-drive car has a Cardan shaft. Cardan is just a fancy name for a universal or U-joint, after this Italian fellow named Cardano back in the Renaissance. It is also called a Hooke's joint after the person who gave Isaac Newton a hard time about his publication on a theory of gravity. The Cardan shaft has a pair of Cardans (or simply U-joints) at each end of a transmission shaft. The Cardan shaft is constant velocity when the ends are translated up and down or side-to-side but not ivoted.
A true constant velocity shaft has a pair of full-fledged constant velocity joints at each end along with a spline to allow the effective length of the shaft to change. You have a pair of such constant velocity shafts for a total of 4 constant-velocity (CV) joints in your front-drive car. The Cardan shaft is not usable in this application because not only do the wheels go up and down over bumps, they also turn as you steer the car with the front wheels, and the vibration resulting from a Cardan shaft would be unacceptable.
There are some theoretical reasons why a universal joint is not constant velocity when there is a shaft deflection angle, which makes it unusable stand-alone for most mechanical power transmission applications. There are also theoretical reasons why the pairing of universal joints in the Cardan shaft is constant velocity when the shafts translate up and down, side-to-side, or when the translation is held fixed but the shafts are somehow constrained to point in conjugate (mirror image) directions. The Cardan shaft cannot translate and change pointing direction at the same time and stay constant velocity.
Australian scientist Kenneth Hunt wrote a paper explaining the theoretical principles behind all constant velocity joints, and how you can make self-contained joints or mechanical couplings that have the properties of the double U-joint of Cardan shaft and also constrain the shafts to the proper alignment. There are also theoretical reasons why a single constant velocity joint of the type Hunt described cannot articulate both in translation and in pointing direction at the same time -- you need a pairing of such CV joints to do that, and that is what you have in the front-drive automobile.
CV joints to transmit the torque required for railroad applications are a challenging design problem -- you can't use the ball-bearing type of CV joint from a car (Rzeppa, Bendix-Weiss) without squashing the ball bearings. My papa designed a full six-axis double CV-joint with spline shaft mechanical transmission for the roller test stand at the US DOT rail test facility in Pueblo, Colorado. It was this massive mechanism with hydrostatic bearings that was constant velocity, and met extreme specs for mechanical stiffness, absence of vibration, and torque levels. Part of the reason for this was Federal Government specsmanship, where they wanted this test stand to be usable "for all time", and the spec was something like 25 percent adhesion at 50 ton axle load at 300 MPH. No one with any sanity would build an electric locomotive with 50 ton axle load for 300 MPH HSR, but Poppa thought that 5 percent adhesion was the best you could count on for HSR without getting into a dangerous high-speed wheel slide, but modern wheel slip controls have pushed adhesion well beyond 25 percent, although perhaps not at speed.
So, the ultimate HSR mechanical drive would be something akin to the massive automotive-style double-CV joint-and-spline developed by Poppa, but some compromises are probably required for practical railroad operations.
The European manufacturers offer updated versions of quill drive from the GG-1, which had been superceded in US practice with the all-purpose nose-hung traction motor. What the quill refers to is the hollow tube surrounding the axle -- the axle is allowed to move relative to the concentric quill and the motor is geared to the quill, reducing the unsprung mass. The GG-1 use flexible springs to connect the quill to the axle, and I read that this was a major maintenance item.
The Europeans appear to have some kind of multi-link connection between quill and axle, which appears to be another version of a translational constant-velocity drive, in theoretical principle much like the Cardan shaft. For another variant on the quill drive, do a Google to look up "Buchli drve."
At one time we thought that steam locomotive (and early electric) side rod drive "pounded the rails", and steam locomotives may have varied between two, three, and four cylinder designs and with respect to different quality of balancing in that respect. Now we know that nose-suspended traction motors "pound the rails." Who knew? Maybe the modern theory of constant-velocity couplings will bring back some form of side-rod and jackshaft (patented by Thomas Crampton, of those big-wheel French and Belgian steam locomotives from the 1840's) as the ideal HSR drive. So (get ready for a bad pun), what goes around eventually comes around.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Paul Milenkovic oltmanndJerry PierBody-mounted motors are best followed by truck mounted. The Acela has truck mounting and the Turboliners,with hydraulic drive, have only the partial weight of the cardan shafts and the axle gear boxes.. Does truck mounted include any differentiation between axle hung (nose suspended) and not? If I remember right, the AEM-7s have frame mounted motors that are not nose suspended. I would think this would be almost as good at body mounted - having the motors between the primary and secondary suspension. The fellow in the office next to mine is doing his PhD research on some manner of electric drives. His "day job" has been with United Technologies Hamilton Sunstrand where electric drives are supposed to be eliminating all of the costly and maintenance-intensive hydraulic motors on airplanes. I was giving him a hard time the other day, for all of the advances in motor design and the use of electronics to provide variable-speed control of AC motors, there is renewed interest in some form of flexible mechanical drive to get between the motor shaft and wheels of high-speed trains on account of the unsprung mass hammer-blow problem. He was "pulling my chain" for my interest in constant-velocity couplings, saying that if the power transmitted by high tension power lines were done with mechanical shafts, the shafts would have to be bigger in diameter than barrels. Of course one would not contemplate anything but electric transmission to get power from one geographic area to the next, but mechanical transmission appears to not be going away anytime soon, even people thought it would, for transmission over varying distances of feet or even inches in rail and automotive suspension. Your traditional solid-axle rear-drive car has a Cardan shaft. Cardan is just a fancy name for a universal or U-joint, after this Italian fellow named Cardano back in the Renaissance. It is also called a Hooke's joint after the person who gave Isaac Newton a hard time about his publication on a theory of gravity. The Cardan shaft has a pair of Cardans (or simply U-joints) at each end of a transmission shaft. The Cardan shaft is constant velocity when the ends are translated up and down or side-to-side but not ivoted. A true constant velocity shaft has a pair of full-fledged constant velocity joints at each end along with a spline to allow the effective length of the shaft to change. You have a pair of such constant velocity shafts for a total of 4 constant-velocity (CV) joints in your front-drive car. The Cardan shaft is not usable in this application because not only do the wheels go up and down over bumps, they also turn as you steer the car with the front wheels, and the vibration resulting from a Cardan shaft would be unacceptable. There are some theoretical reasons why a universal joint is not constant velocity when there is a shaft deflection angle, which makes it unusable stand-alone for most mechanical power transmission applications. There are also theoretical reasons why the pairing of universal joints in the Cardan shaft is constant velocity when the shafts translate up and down, side-to-side, or when the translation is held fixed but the shafts are somehow constrained to point in conjugate (mirror image) directions. The Cardan shaft cannot translate and change pointing direction at the same time and stay constant velocity. Australian scientist Kenneth Hunt wrote a paper explaining the theoretical principles behind all constant velocity joints, and how you can make self-contained joints or mechanical couplings that have the properties of the double U-joint of Cardan shaft and also constrain the shafts to the proper alignment. There are also theoretical reasons why a single constant velocity joint of the type Hunt described cannot articulate both in translation and in pointing direction at the same time -- you need a pairing of such CV joints to do that, and that is what you have in the front-drive automobile. CV joints to transmit the torque required for railroad applications are a challenging design problem -- you can't use the ball-bearing type of CV joint from a car (Rzeppa, Bendix-Weiss) without squashing the ball bearings. My papa designed a full six-axis double CV-joint with spline shaft mechanical transmission for the roller test stand at the US DOT rail test facility in Pueblo, Colorado. It was this massive mechanism with hydrostatic bearings that was constant velocity, and met extreme specs for mechanical stiffness, absence of vibration, and torque levels. Part of the reason for this was Federal Government specsmanship, where they wanted this test stand to be usable "for all time", and the spec was something like 25 percent adhesion at 50 ton axle load at 300 MPH. No one with any sanity would build an electric locomotive with 50 ton axle load for 300 MPH HSR, but Poppa thought that 5 percent adhesion was the best you could count on for HSR without getting into a dangerous high-speed wheel slide, but modern wheel slip controls have pushed adhesion well beyond 25 percent, although perhaps not at speed. So, the ultimate HSR mechanical drive would be something akin to the massive automotive-style double-CV joint-and-spline developed by Poppa, but some compromises are probably required for practical railroad operations. The European manufacturers offer updated versions of quill drive from the GG-1, which had been superceded in US practice with the all-purpose nose-hung traction motor. What the quill refers to is the hollow tube surrounding the axle -- the axle is allowed to move relative to the concentric quill and the motor is geared to the quill, reducing the unsprung mass. The GG-1 use flexible springs to connect the quill to the axle, and I read that this was a major maintenance item. The Europeans appear to have some kind of multi-link connection between quill and axle, which appears to be another version of a translational constant-velocity drive, in theoretical principle much like the Cardan shaft. For another variant on the quill drive, do a Google to look up "Buchli drve." At one time we thought that steam locomotive (and early electric) side rod drive "pounded the rails", and steam locomotives may have varied between two, three, and four cylinder designs and with respect to different quality of balancing in that respect. Now we know that nose-suspended traction motors "pound the rails." Who knew? Maybe the modern theory of constant-velocity couplings will bring back some form of side-rod and jackshaft (patented by Thomas Crampton, of those big-wheel French and Belgian steam locomotives from the 1840's) as the ideal HSR drive. So (get ready for a bad pun), what goes around eventually comes around.
I know, Elevators are not Locomotives. United Technologies (UTX) is one of our nation's largest (57th on Forbes 500 list) and one of the best run U.S.corporations. I know, I'm retired now after 47 years with the Otis Elevator Division of UTX and I enjoyed working for the industry leader. To accelerate an elevator to full speed at a constance rate of acceleration, slow down and stop within 3mm of floor level demands the tightest motor control. Today new elevator equipment is all VVVF control driving gearless AC traction motors. Worm Gear machines are still offered for some slow speed elevators while SCR drives are sold for modernizing older DC motors. The DC Gearless traction motors in the "Twin Towers" weighted 26 tons each. For good or bad, UTX also designed and built the UA Turbotrains. In the 1960s and 70s we had engineers that felt Hydraulics drives were the way to control machinery, they lost, today it's "fly by wire".
Just a reminder that the PCC streetcar does not use nose suspended traction motors. The two motors on each truck are mounted longitudinally and drive through some kind of worm or spicer geatbox to each axle. But the unsprung weight is substantially reduced by resilient wheels.
Arne't then, resilient wheels an absolute requirement for the "wheel motor" as developed by Alstom, Magnet Motor, and Energy Storage Systems?
Yeah, I have seen a PCC truck, I believe it was at the Illinois Railway Museum some while ago. Each traction motor is truck mounted, and it drives the right angle gearbox through a Cardan shaft, that shaft with the universal joint at each end.
Something tells me that the original Bullet Train in Japan used this kind of arrangement, but I would need to confirm it.
I am not so sure that the resilient wheel is that great for railroad use. A one-time neighbor who had worked for Rockwell talked about doing a prototype streetcar in Detroit and of sending a wheel through a drug store window when it came off. A resilient wheel failure resulted in a fatal accident on the German ICE train. OK, two incidents does not make a pattern, but let's just say there are concerns.
It's more than just signalling. There are other engineering issues. For example, the degree of curve banking required for high speed passenger trains may be inconsistent with operation of modern, high center of gravity freight cars. Also, there's a difference in design philosophy. A freight railroad will typically be designed to minimize grades as much as reasonably possible, and this often involves increasing curvature to reduce grades. Grades aren't as big a problem for high speed rail, but curvature is, because curvature limits maximum speed The " grade vs curvature" issue won't be that evident on lines with relative flat terrain, but it would be very important in hilly or mountainous terrain.
There's also a maintenance issue. High speed passenger service requires that track be maintained to very tight tolerances. But operating heavy freight trains on the same tracks makes it difficult if not impossible to keep the track structure within those tolerances. Anyone who's ridden an Amtrak train over trackage which sees heavy coal traffic has experienced this problem first hand
oltmanndThe Aug Railway Age has a good article that compares the track maintenance costs for various mixed frt/pass conditions. Try this http://www.nxtbook.com/nxtbooks/sb/ra0809/#/28
http://www.nxtbook.com/nxtbooks/sb/ra0809/#/28
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DMUinCTReaching back 15 years, Metroliner Service pulled by AEM7 locomotives cruised at 125 mph. I've been onboard when a Metroliner streached out to 129 mph (fudge factor). 10 years ago, with track work complete between New Haven and Boston, but without the Catenary ready, F40PH diesels were geared for and ran at 110 mph.
And, today, Northeast Regional cruises at 125 mph and Acela at 135 mph (or 150 mph). Except for the older cars I always thought of Northeast Regional/Direct/Whatever as Metroliner 3.
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