Times at actual high speed?

[MattW]

I was wondering, just how long do high speed services around the world (particularly TGV and ICE) get to maintain their top speeds between stations? The reason I ask is because I was running a hypothetical 220mph corridor across south Georgia, and the math only gave 8-10 minutes at 220mph given acceleration and deceleration. Given that the combined areas of Alabama, South Carolina, and Georgia is slightly greater than the area of Germany, it made me question just how long existing high speed trains (which admittedly most are not 220mph yet) spend at top speed over their run.

 

[George Harris]

I don't know what you are using as a power to weight ratio, aerodynamic resistance, other components of rolling resistance, adhesion, maximum acceleration and braking rates, but you should have more than a few miles at the maximum speed if you use appropriate values for these parameters. 220 mph, actually 350 km/hr which is more like 217 mph, is the limit for much of the new high speed railway in China.

 

[jis]

I was wondering, just how long do high speed services around the world (particularly TGV and ICE) get to maintain their top speeds between stations? The reason I ask is because I was running a hypothetical 220mph corridor across south Georgia, and the math only gave 8-10 minutes at 220mph given acceleration and deceleration. Given that the combined areas of Alabama, South Carolina, and Georgia is slightly greater than the area of Germany, it made me question just how long existing high speed trains (which admittedly most are not 220mph yet) spend at top speed over their run.

I have to look this up again but AFAIR a typical Paris - Lille train spends about 30 to 40 mins out of its total run of 1 hr, at the top speed of 300kph. But you have to remember that a typical TGV is almost a rocket when it comes to acceleration and deceleration when compared to anything that runs in the US so far. The power to weight rations are almost of a different order, even compared to Acelas.

 

[amtrakwolverine]

Other country's HSR trains are light as a feather compared to our bricks on rails we have here.

 

[George Harris]

Other country's HSR trains are light as a feather compared to our bricks on rails we have here.

That is a considerable exaggeration. Yes, current US trains are considerably heavier than current European trains, but the difference in weight is not really as great as they would claim. The main issue with European equipment builders is that they want to be able to sell their "straight out of the box" equipment without having to meet US crashworthiness and evacuation requirements. Their current designs do not even come close.

However just because our current equipment is significantly heavier than their current equipment does not mean that new designed equipment has to be. The standards can be met without the huge weigth increase that their propoganda claims. Soem weight increase, probably so. However, the major portion of train resistance is aerodynamic, so shape is far more inportant than vehicle weight other than in the acceleration and braking portions of the route, and even here aerodynamics still plays a major part.

A large part of the Acela issues that were blamed on train weight were in reality more of a lack of understanding of the service conditions. In general, in the European lines the trains accelerate to speed and stay there. This luxury does not exist on the Northeast Corridor. In order to minimize run time, the trains are almost constantly braking and accelerating. Thus the braking system wears out a lot faster. The supplier of the system was surprised?? He should not have been.

 

[jis]

A large part of the Acela issues that were blamed on train weight were in reality more of a lack of understanding of the service conditions. In general, in the European lines the trains accelerate to speed and stay there. This luxury does not exist on the Northeast Corridor. In order to minimize run time, the trains are almost constantly braking and accelerating. Thus the braking system wears out a lot faster. The supplier of the system was surprised?? He should not have been.

I agree with that being an issue. However I still don't understand why they chose to have considerably worse power/weight ratio for the Acelas, than say for the TGV (just to take a concrete example the TGV Resseau) knowing fully well that they do need to repeatedly accelerate and slow down in the operating conditions on the NEC. Any insights on why they chose to do that? I would really like to know. I have pondered this and not found a cogent reasoning. Was it just cost saving, in a somewhat self defeating way? Incidentally with the addition of two cars per consist this situation will become even worse.

 

[Green Maned Lion]

Talking purely on a guessing basis, since I don't know if George knows any pertinent information on the subject (if he does, ignore what I'm saying), I logically come out with this:

The Acela uses a modified LRC structure. It was designed on a shoestring budget to compete with a vastly superior set of competitors from overseas. Bombardier, it has been admitted, got its contract primarily on the basis of financing and diplomacy. I doubt they spent any more than they had to designing it. It didn't have to work well so long as it met the terms of the various agreements.

In essence, cost cutting, but not self defeating, since it isn't self defeating when at the time the competition for building was in the corridors of politics, not merit.

 

[George Harris]

Talking purely on a guessing basis, since I don't know if George knows any pertinent information on the subject (if he does, ignore what I'm saying), I logically come out with this:

The Acela uses a modified LRC structure. It was designed on a shoestring budget to compete with a vastly superior set of competitors from overseas. Bombardier, it has been admitted, got its contract primarily on the basis of financing and diplomacy. I doubt they spent any more than they had to designing it. It didn't have to work well so long as it met the terms of the various agreements.

In essence, cost cutting, but not self defeating, since it isn't self defeating when at the time the competition for building was in the corridors of politics, not merit.

You have a lot of truth in what you say, and I will not be more specific than that in where you hit and where you missed.

 

[MattW]

Ok, I see what you all are getting at. I guess the question should be what is the typical/minimum distance between stations on the high speed lines? Also, what would be a good acceleration number to use for trains that reach over 150mph? I had always used 1 mile per hour per second which seemed to work well.

 

[jis]

Ok, I see what you all are getting at. I guess the question should be what is the typical/minimum distance between stations on the high speed lines? Also, what would be a good acceleration number to use for trains that reach over 150mph? I had always used 1 mile per hour per second which seemed to work well.

For the N700 Shinkansen it is 2.6 km/h/s. But then Shinkansens, specially the stopping ones on the Tokaido Shinkansen, have pretty frequent stops too, e.g. Tokyo, Shinagawa, Shin Yokohama, Odawara etc. etc. on the way to Osaka. Those are the Kodamas. The Hikaris have many fewer stops, and some Nozomis run pretty much non-stop I believe from Tokyo Central to Osaka, while a few stop at Shin Yokohama.

 

[George Harris]

As a sanity check on the numbers: the Taiwan High Speed Railway is 210 miles from end to end. The maximum speed limit is 300 km/h = 186 mph. Approximately 12 miles at the extreme ends have lower speed limits, down to 50 mph for short distances.

A train making 2 stops, one in Suburban Taipei and the other stop at Taichung, about the half way point, takes 1 hour 36 minutes

A train making all stops, 6 stops, takes 2 hours flat.

They run 5 trains per hour. The schedule is easily achievable. Normal dwell time appears to be about 2 mainutes at all stops except Taichung, where it is three minutes.

 

[TVRM610]

Talking purely on a guessing basis, since I don't know if George knows any pertinent information on the subject (if he does, ignore what I'm saying), I logically come out with this:

The Acela uses a modified LRC structure. It was designed on a shoestring budget to compete with a vastly superior set of competitors from overseas. Bombardier, it has been admitted, got its contract primarily on the basis of financing and diplomacy. I doubt they spent any more than they had to designing it. It didn't have to work well so long as it met the terms of the various agreements.

In essence, cost cutting, but not self defeating, since it isn't self defeating when at the time the competition for building was in the corridors of politics, not merit.

Bombardier does not have a very good TRACK record. They also built the Las Vegas Monorail system which has had a huge amount of mechanical problems, including large pieces falling of the trains during testing. They also had a pretty major design flaw in the new Disneyland monorails that were built a year or two ago.

I have to say, I like the Acela though. At least it does run at 150, for the USA, that in itself is an accomplishment.

 

[PRR 60]

Bombardier does not have a very good TRACK record. They also built the Las Vegas Monorail system which has had a huge amount of mechanical problems, including large pieces falling of the trains during testing. They also had a pretty major design flaw in the new Disneyland monorails that were built a year or two ago.

I have to say, I like the Acela though. At least it does run at 150, for the USA, that in itself is an accomplishment.

The Disneyland Mark VII monorail transets were built by Dynamic Structures, a British Columbia firm that constructs amusement park rides. I am not aware of Bombadier having a part of the project.

 

[Train person]

Paris to Marseille is 3 hours for a non stop service.

Apart from the first and last 10-15 minutes departing Gare de Lyon and gaining the LGV and running into Marseille St Charles then after you accelerate to line speed you could run over 2 hours, maybe 2 hours 30 at 167- 200mph.

 

[jis]

Paris to Marseille is 3 hours for a non stop service.

Apart from the first and last 10-15 minutes departing Gare de Lyon and gaining the LGV and running into Marseille St Charles then after you accelerate to line speed you could run over 2 hours, maybe 2 hours 30 at 167- 200mph.

Have you actually seen the speed profile of the line? I have not recently. but from many year ago. I could have faulty memory, but I seem to recall that there are two places where there are permanent restrictions of 250kph or some such because of vertical curvature,i.e. faster than that and the train would risk losing contact with the rail, and there are at least two more junctions where there are minor speed restrictions. There may be others too, I don't remember.

 

[George Harris]

Paris to Marseille is 3 hours for a non stop service.

Apart from the first and last 10-15 minutes departing Gare de Lyon and gaining the LGV and running into Marseille St Charles then after you accelerate to line speed you could run over 2 hours, maybe 2 hours 30 at 167- 200mph.

Have you actually seen the speed profile of the line? I have not recently. but from many year ago. I could have faulty memory, but I seem to recall that there are two places where there are permanent restrictions of 250kph or some such because of vertical curvature,i.e. faster than that and the train would risk losing contact with the rail, and there are at least two more junctions where there are minor speed restrictions. There may be others too, I don't remember.

These would be crest vertical curves, not sag vertical curves. The French standard vertical curve rate of change is at a higher rate than almost everybody else's. (They, and most of Europe, also set vertical curves by radius rather than by rate of change in grade per unit length, which is normal US practice.) It is not likely that there is any danger of losing contact with the rail, as that would take a very high rate of change in grade, or low vertical radius if you want to put it in their terms. The likely explanation is that the vertical acceleration going over the crest grade reduces the loading on the rails sufficiently that the remaining adhesion does not allow the full braking rate to be used.

Jis, I will respond to the issues raised in the other post concerning Eschede later. That requires more thought than I can handle on a Saturday morning.

 

[train person]

Have you actually seen the speed profile of the line? I have not recently. but from many year ago. I could have faulty memory, but I seem to recall that there are two places where there are permanent restrictions of 250kph or some such because of vertical curvature,i.e. faster than that and the train would risk losing contact with the rail, and there are at least two more junctions where there are minor speed restrictions. There may be others too, I don't remember.

There was a lot of work done before the full length of the line opened in 2001 to remove as many speed restrictions on the Paris to Lyon bypass section of the route.

Certainly south of Valence on the newest part it is a 186/200 mph railway.

I am sure I have seen the line profie somewhere,will have to dig it out.

A quick calculation tells me that the journey length is 470 miles, at a dead 3 hours for a flyer that equals 153mph average speed. There's not much scope for dawdling there!

 

[jis]

Jis, I will respond to the issues raised in the other post concerning Eschede later. That requires more thought than I can handle on a Saturday morning.

George thanks. I hope you don't see my other post in response to yours as an attack or anything. That was not my intention at all. My only intention is to raise some questions about the complex issues involved. Some of the things in the area of crash protection and survivability is just not as cut and dried, black and white as people make it out to be. Looking forward to increase the level of my (and of course our collective) understanding from your feedback and the dialog that might follow.

Have you actually seen the speed profile of the line? I have not recently. but from many year ago. I could have faulty memory, but I seem to recall that there are two places where there are permanent restrictions of 250kph or some such because of vertical curvature,i.e. faster than that and the train would risk losing contact with the rail, and there are at least two more junctions where there are minor speed restrictions. There may be others too, I don't remember.

There was a lot of work done before the full length of the line opened in 2001 to remove as many speed restrictions on the Paris to Lyon bypass section of the route.

Certainly south of Valence on the newest part it is a 186/200 mph railway.

I am sure I have seen the line profie somewhere,will have to dig it out.

A quick calculation tells me that the journey length is 470 miles, at a dead 3 hours for a flyer that equals 153mph average speed. There's not much scope for dawdling there!

Oh yes, absolutely. I have no doubt that the line south of Valence is a much better profile than the classic Sud-Est segment, since the lessons learned from Sud-Est were incorporated in designing the profile. I have heard from at least one SNCF engineer that they regretted the vertical curvatures that they used on the Sud-Est segment.

It would sure be nice to see what the speed profile is. And yes, there is not much loose time available there, but OTOH you do not require to run full speed all the way to meet the schedule either. Typically there is some amount of contingency in the 3 hour schedule, is what I have heard. This would be so called difference between the booked speed and the max allowed speed in the schedule.

Incidentally because SNCF has the practice of having so called White Hours in the schedule when they just shut the entire railroad down for maintenance, instead of taking a segment here and a segment there out of service, they are able to minimize the contingency in schedules, since they don;t have to account for segment outage and crossover times etc. Fascinating area of scheduling philosophies as they differ dramatically between even SNCF and DB!

 

[George Harris]

Jis, I will respond to the issues raised in the other post concerning Eschede later. That requires more thought than I can handle on a Saturday morning.

George thanks. I hope you don't see my other post in response to yours as an attack or anything. That was not my intention at all. My only intention is to raise some questions about the complex issues involved. Some of the things in the area of crash protection and survivability is just not as cut and dried, black and white as people make it out to be. Looking forward to increase the level of my (and of course our collective) understanding from your feedback and the dialog that might follow.

Did not take it as an attack. Incidentilly: The standard "heavyweight" coach with vestibules effectively had an about four foot crumple zone on each end, whether by intention or by accident.

Incidentally because SNCF has the practice of having so called White Hours in the schedule when they just shut the entire railroad down for maintenance, instead of taking a segment here and a segment there out of service, they are able to minimize the contingency in schedules, since they don;t have to account for segment outage and crossover times etc. Fascinating area of scheduling philosophies as they differ dramatically between even SNCF and DB!

Daytime also or only the middle of the night? The middle of the night time as is done on many/most transit system is the norm for a lot of the high speed lines. Look at a Shinkansen schedules and see what you find between midnight and 6:00am. Nothing, unless something has changed recently. Midnight to 4:00am or therabouts is the work window, with the remaining an allowance for surprises, contingencies, and a "sweep" to run ahead of the first schedule to see if all is properly in place for the resumption of normal traffic.

 

[train person]

Oh yes, absolutely. I have no doubt that the line south of Valence is a much better profile than the classic Sud-Est segment, since the lessons learned from Sud-Est were incorporated in designing the profile. I have heard from at least one SNCF engineer that they regretted the vertical curvatures that they used on the Sud-Est segment.

It would sure be nice to see what the speed profile is. And yes, there is not much loose time available there, but OTOH you do not require to run full speed all the way to meet the schedule either. Typically there is some amount of contingency in the 3 hour schedule, is what I have heard. This would be so called difference between the booked speed and the max allowed speed in the schedule.

Incidentally because SNCF has the practice of having so called White Hours in the schedule when they just shut the entire railroad down for maintenance, instead of taking a segment here and a segment there out of service, they are able to minimize the contingency in schedules, since they don;t have to account for segment outage and crossover times etc. Fascinating area of scheduling philosophies as they differ dramatically between even SNCF and DB!

If you click on this, then Lignes a grand vitesse it shows you the track plan, gradient profile and in most cases the speed limit for each part of the TGV network.

http://florent.brisou.pagesperso-orange.fr/Lignes.htm

As for white hours, its a lot lot better than it used to be, certainly a look at departures south from Paris Lyon shows departures every hour, although between 1200-1300 there are only 3 southbound trains, and the last southbound train is around 2100. I like to think the low numbers of rains at midday is due to proper and fine lunching!

As for speed, a few weeks ago I used TGV and Eurostar and the TGV ran north of Lyon at no more than 180mph and arrived spot on time. The Eurostar left a few minutes late and ran to Lille at the full 186mph and then 170-175 from Lille to the tunnel.