Sunset Limited

[amtrakwolverine]

How many trains are there to Richmond each day? 5 or 6?

There's potential for a lot more than 5 or 6 if we could get the speed up to something like 250-350 MPH. Washington Union Station to the Atlanta Airport via Richmond, Greensboro, Charlotte, and Greenville is apparently 647 highway miles. A train making various stops in the DC area and the Atlanta area and running express in between might well be gotten under 3 hours.

if were going to run trains that fast then the following needs upgrading.

1. either eliminate all grade crossings or build overpasses.

2. in cab signals and ATS etc

3. seperate track for pax trains only. no freight at all.

 

[Joel N. Weber II]

if were going to run trains that fast then the following needs upgrading.
1. either eliminate all grade crossings or build overpasses.

2. in cab signals and ATS etc

3. seperate track for pax trains only. no freight at all.

And you need major curve straightening to the extent that you probably can't use any existing railroad right of way.

 

[George Harris]

In my definition of a DMU/EMU, they have traction motors in each car. That design, inherrently:
1) provides for better acceleration

2) does not reduce performance when you increase train length

3) provides for much better traction on slippery rails.

Time and time again, we watch ALP-44 and ALP-46 trains run behind on NJT during the fall and winter, while the Arrows remain on schedule. You get better acceleration when the traction is spread out through the whole train. Hey, Mr. Harris, wanna back me up on this point?

Can't do it.

Most but not all rapid transit cars have all axles motored, for example WMATA, but most of the long distance "EMU" trains do not.

Depending upon the trainset, the general proportion on the Shinkansen trains is between 2/3 and 3/4 axles powered. The end cars for all sets for which I have information are unpowered. There is a very good reason for this. The lead car will have lower traction possible than any other, as it will be the first to deal with any water, etc. on the rail. As the rails are cleaned by the passage of wheels, each car along the train will have slightly better adhesion.

Adhesion can be taken as a percentage of the weight on the powered axle. Adhesion also declines with speed. The Japanese have studied this and have formulas that they use in determining the practical number of powered axles and power per axle for a given trainset.

The reason that true loco hauled trains lose their practicality at high speeds is that the required power per axle results in the need for an impractically high weight per axle so that the power can be usable.

 

[jis]

Most but not all rapid transit cars have all axles motored, for example WMATA, but most of the long distance "EMU" trains do not.

Interestingly, even the Arrow III married pairs that NJT has has only 6 of the 8 axles powered.

The reason that true loco hauled trains lose their practicality at high speeds is that the required power per axle results in the need for an impractically high weight per axle so that the power can be usable.

Again, interestingly even the first TGV sets were hybrids in that sense since the first two axles of the non-power-head portion of the train sets were powered, fed from the adjacent power-head

Indeed the best way to describe these situations is "distributed power"and that is indeed a very valuable principle get the right mix of weight, traction and speed, as explained very nicely by Mr. Harris. And as I and others have stated before, that issue is somewhat orthogonal to the issue of whether the sets can MU consists such that the entire lot can be controlled from the front cab.

 

[Neil_M]

Again, interestingly even the first TGV sets were hybrids in that sense since the first two axles of the non-power-head portion of the train sets were powered, fed from the adjacent power-head

The Eurostar sets have the same set up, 4 powered axles on the power car and the first 2 axles of the adjacent trailer.

 

[Green Maned Lion]

In my definition of a DMU/EMU, they have traction motors in each car. That design, inherrently:
1) provides for better acceleration

2) does not reduce performance when you increase train length

3) provides for much better traction on slippery rails.

Time and time again, we watch ALP-44 and ALP-46 trains run behind on NJT during the fall and winter, while the Arrows remain on schedule. You get better acceleration when the traction is spread out through the whole train. Hey, Mr. Harris, wanna back me up on this point?

Can't do it.

Most but not all rapid transit cars have all axles motored, for example WMATA, but most of the long distance "EMU" trains do not.

Depending upon the trainset, the general proportion on the Shinkansen trains is between 2/3 and 3/4 axles powered. The end cars for all sets for which I have information are unpowered. There is a very good reason for this. The lead car will have lower traction possible than any other, as it will be the first to deal with any water, etc. on the rail. As the rails are cleaned by the passage of wheels, each car along the train will have slightly better adhesion.

Adhesion can be taken as a percentage of the weight on the powered axle. Adhesion also declines with speed. The Japanese have studied this and have formulas that they use in determining the practical number of powered axles and power per axle for a given trainset.

The reason that true loco hauled trains lose their practicality at high speeds is that the required power per axle results in the need for an impractically high weight per axle so that the power can be usable.

Actually, you just explained exactly what I was trying to say. I plead guilty to lack of exact knowledge and an inability to communicate- but not to the thought in my mind being false.

 

[Neil_M]

Actually, you just explained exactly what I was trying to say. I plead guilty to lack of exact knowledge and an inability to communicate- but not to the thought in my mind being false.

Just admit you were wrong. It is allowed to happen.

 

[Green Maned Lion]

It sure is. This just isn't an example of it.

 

[Ryan]

Most but not all rapid transit cars have all axles motored, for example WMATA, but most of the long distance "EMU" trains do not.
Depending upon the trainset, the general proportion on the Shinkansen trains is between 2/3 and 3/4 axles powered. The end cars for all sets for which I have information are unpowered. There is a very good reason for this. The lead car will have lower traction possible than any other, as it will be the first to deal with any water, etc. on the rail. As the rails are cleaned by the passage of wheels, each car along the train will have slightly better adhesion.

Adhesion can be taken as a percentage of the weight on the powered axle. Adhesion also declines with speed. The Japanese have studied this and have formulas that they use in determining the practical number of powered axles and power per axle for a given trainset.

The reason that true loco hauled trains lose their practicality at high speeds is that the required power per axle results in the need for an impractically high weight per axle so that the power can be usable.

Since you brought up WMATA, they are asking bidders for the new 7000 series cars to provide some analysis in their bids on their married pairs having some number of unpowered axles, so this is something that they're considering as well.

 

[AlanB]

Most but not all rapid transit cars have all axles motored, for example WMATA, but most of the long distance "EMU" trains do not.
Depending upon the trainset, the general proportion on the Shinkansen trains is between 2/3 and 3/4 axles powered. The end cars for all sets for which I have information are unpowered. There is a very good reason for this. The lead car will have lower traction possible than any other, as it will be the first to deal with any water, etc. on the rail. As the rails are cleaned by the passage of wheels, each car along the train will have slightly better adhesion.

Adhesion can be taken as a percentage of the weight on the powered axle. Adhesion also declines with speed. The Japanese have studied this and have formulas that they use in determining the practical number of powered axles and power per axle for a given trainset.

The reason that true loco hauled trains lose their practicality at high speeds is that the required power per axle results in the need for an impractically high weight per axle so that the power can be usable.

Since you brought up WMATA, they are asking bidders for the new 7000 series cars to provide some analysis in their bids on their married pairs having some number of unpowered axles, so this is something that they're considering as well.

I'm sure that's a cost savings issue that they're thinking about, not an adhesion issue.

 

[Bigval109]

Most but not all rapid transit cars have all axles motored, for example WMATA, but most of the long distance "EMU" trains do not.
Depending upon the trainset, the general proportion on the Shinkansen trains is between 2/3 and 3/4 axles powered. The end cars for all sets for which I have information are unpowered. There is a very good reason for this. The lead car will have lower traction possible than any other, as it will be the first to deal with any water, etc. on the rail. As the rails are cleaned by the passage of wheels, each car along the train will have slightly better adhesion.

Adhesion can be taken as a percentage of the weight on the powered axle. Adhesion also declines with speed. The Japanese have studied this and have formulas that they use in determining the practical number of powered axles and power per axle for a given trainset.

The reason that true loco hauled trains lose their practicality at high speeds is that the required power per axle results in the need for an impractically high weight per axle so that the power can be usable.

Since you brought up WMATA, they are asking bidders for the new 7000 series cars to provide some analysis in their bids on their married pairs having some number of unpowered axles, so this is something that they're considering as well.

I'm sure that's a cost savings issue that they're thinking about, not an adhesion issue.

So getting back to the sunset limited. Is there any chance of it returning to coast to coast say within the next couple of years?

 

[Green Maned Lion]

It might- I hope not - I suspect Amtrak's finding will be that service should be done by a separate train, they will claim they don't have the equipment for that at the moment- they don't have the equipment to start a seperate daily train between NOL and MIA - and will commit to starting it as soon as the new Viewliners are delivered.