Consist Question

[Joel N. Weber II]

It is interesting to read this post and then compare how many locomotives Amtrak uses to haul x number of coaches vs. Indian Railways, for example. I have watched many videos of them on Youtube, and am amazed how many cars they haul with their locomotives. They often use one WAP4 electric locomotive to haul 24 coaches. The WAP4 is 5000 horsepower and is rated to haul up to 26 coaches at 160 kph (100 mph). Amtrak's AEM 7 is 7000 hp; I don't know how many coaches they are rated to haul, but I don't think they haul anywhere near that number anywhere on the NEC.

Some other factors to consider, in addition to the weight of the coaches as Alan mentions, are how well the train accelerates, and what grades are involved. I'd be surprised if a single AEM7 can't haul 24 Amfleet coaches at 100 MPH on track with a 0% grade, given enough time to accelerate up to that 100 MPH.

 

[battalion51]

I believe given the capabilities of the converters the AEM-7 can provide HEP power for about 15 cars. Over that the converters can't get enough HEP to the train. Thus why longer trains like the New Jersey Chamber of Commerce get two motors. Part of it is ability to accelerate, part of it is HEP conversion capability.

 

[jis]

It is interesting to read this post and then compare how many locomotives Amtrak uses to haul x number of coaches vs. Indian Railways, for example. I have watched many videos of them on Youtube, and am amazed how many cars they haul with their locomotives. They often use one WAP4 electric locomotive to haul 24 coaches. The WAP4 is 5000 horsepower and is rated to haul up to 26 coaches at 160 kph (100 mph). Amtrak's AEM 7 is 7000 hp; I don't know how many coaches they are rated to haul, but I don't think they haul anywhere near that number anywhere on the NEC.
Maybe one reason is (I think) the WAP4 uses an extra power car where the AEM 7 generates HEP itself?

That figure of 160kph for 26 coaches is of only theoretical interest since there is no 26 coach train in India that is allowed a MAS of 160kph. 120kph is about it for 26 coaches at present, and even those will typically get a WAP-7 these days which is somewhere between 5 and 6k HP, depending on when it was built. A WAP4 pulling 26 coaches will not accelerate anywhere near as fast as a typical Amtrak train. As a matter of fact a more capable WAP5 was not good enough for IR because it had tractive effort problems due to its light weight and only 4 axles. That is why IR developed the WAP7 which is a re-geared and re-programmed WAG5 (originally a freight engine) which is much heavier and has 6 axles, and they appear to be happy with that.

India doesn't have FRA rules in effect, therefore their cars weigh less than Amtrak cars do, that allows their engines to pull more cars.

Actually Indian coaches are quite surprisingly not as light as one would imagine. The ICF Corten coaches are in the vicinity of 50 - 55 tons, and the new LHB/Alstom Stainless Steel coaches are around 44 tons (40tonnes).

Again, mainly it is because much slower acceleration is tolerated and also MAS is seldom above 110kph except for few select trains which are rated for 120 or 130, and I think one or two as high as 140kph, that one can get away with less HP per unit weight. The higher speed trains are usually way shorter than 26 coaches and always get premium power like WAP7s or WAP5s.

I believe that an AEM-7 can haul around 15 to 16 cars without too much trouble. And the AEM-7 doesn't generate HEP power, it just converts the catenary power to HEP. Unlike with a diesel engine, you're not stealing power from the traction motors to provide HEP. A P42 is rated for 4,200 HP. However if it's providing HEP, you're probably only getting around 3,700 to 3,800 HP in tractive effort, the remainder is going into HEP.

IR keeps its hotel department and its power department fully separated . Even on trains that use centrally provided hotel power, the hotel power is provided from Generator Cars and not from the locomotive. Locomotives do not have any HEP facility. And then again a preponderance of trains use self-generating coaches which have axle driven alternators that charge up huge banks of batteries slung under the cars to provide power. There are even many varieties of fully air-conditioned coaches which are powered in this way. For such trains of course to quite an extent it is the locomotive that provides the power, but not via a HEP generator but through a slightly higher tractive effort needed to keep things moving. Of course when going downhill you get the power for free.

With an AEM-7 you're getting 7,000 HP regardless of whether or not the motor is also providing HEP. You've got a very large power company at the other end of that long wire, so you can draw as much power as you need provided that you don't overload the electronic equipment in the locomotive.

Actually the limiting factor often is the cooling equipment. The electronics will just keep getting hotter and hotter until there is a spectacular bonfire if the thermostat driven safety cutoff fails to operate.

Another thing about AEM-7s is that while they can do 15-16 cars for Amtrak, if they even thought of trying to pull a 15 car train for NJT people would have a stroke. The acceleration that an ALP-44 which is as capable or better than AEM-7s would be completely unacceptable under NJT-like operating circumstances, but the same is quite OK for Amtrak because their required operating characteristics are quite different from NJT's

 

[printman2000]

Just saw a report on another board where the Texas Eagle (22) was being pulled by a UP locomotive in De Soto, MO. Perfect example of the TE needing two locos.

I only wonder if it's P42 is still able to produce HEP or if they are in the dark.

 

[DAWall]

Just saw a report on another board where the Texas Eagle (22) was being pulled by a UP locomotive in De Soto, MO. Perfect example of the TE needing two locos.
I only wonder if it's P42 is still able to produce HEP or if they are in the dark.

I have a friend that is an Engineer for Amtrak, He works the Cardinal from CHI to IND, and sometimes the Texas Eagle Chi to Stl. He said the Texas Eagle...in his words "Was a Pig" saying he hates how slowly the train accelerates with only one locomotive. And dreaded taking a siding, knowing he was going to lose more time getting it back up to track speed. And bad weather only compounds the problem. He said while the road failures aren't near as bad as they had been, they still happen. He would like to see another unit added to the TE...and thinks it might finally happen, with the extra funding.

 

[warbonnet]

Last week on 14 from LAX\SEA we had two 42's and one unit from the Cascade fleet all the way to Sea. I was surprised to see the Cascade colors in LA!

Wb

 

[jis]

Some other factors to consider, in addition to the weight of the coaches as Alan mentions, are how well the train accelerates, and what grades are involved. I'd be surprised if a single AEM7 can't haul 24 Amfleet coaches at 100 MPH on track with a 0% grade, given enough time to accelerate up to that 100 MPH.

An AEM-7 would have difficulty supplying HEP to 24 coaches though,one would think.

Yes indeed acceleration and gradient are two big factors. All the horsepower in the world is of no use if it cannot be converted reliably into tractive effort.

IR took the trouble to design their own WAP7 after playing around with Bombardier's WAP5 and WAG5, precisely because the Bo-Bo WAG5 simply could not hack it on gradient. I believe they required certain acceleration capabilities on 2% gradient. Apparently the brawnier Co-Co WAP7 manages to pull it off with the usual 18 to 24 car trains on 2% gradients.

I have seen a single WAP7 accelerate an 18 car Rajdhani Express from dead stop at a signal up the gradient between Gaya Jct. and Koderma, quite effortlessly and been quite impressed with its pulling power.

 

[gaspeamtrak]

Some other factors to consider, in addition to the weight of the coaches as Alan mentions, are how well the train accelerates, and what grades are involved. I'd be surprised if a single AEM7 can't haul 24 Amfleet coaches at 100 MPH on track with a 0% grade, given enough time to accelerate up to that 100 MPH.

An AEM-7 would have difficulty supplying HEP to 24 coaches though,one would think.

Yes indeed acceleration and gradient are two big factors. All the horsepower in the world is of no use if it cannot be converted reliably into tractive effort.

IR took the trouble to design their own WAP7 after playing around with Bombardier's WAP5 and WAG5, precisely because the Bo-Bo WAG5 simply could not hack it on gradient. I believe they required certain acceleration capabilities on 2% gradient. Apparently the brawnier Co-Co WAP7 manages to pull it off with the usual 18 to 24 car trains on 2% gradients.

I have seen a single WAP7 accelerate an 18 car Rajdhani Express from dead stop at a signal up the gradient between Gaya Jct. and Koderma, quite effortlessly and been quite impressed with its pulling power.

Jis can you recommend any "YouTube" videos of the WAP7 hauling trains?

 

[AlanB]

Some other factors to consider, in addition to the weight of the coaches as Alan mentions, are how well the train accelerates, and what grades are involved. I'd be surprised if a single AEM7 can't haul 24 Amfleet coaches at 100 MPH on track with a 0% grade, given enough time to accelerate up to that 100 MPH.

An AEM-7 would have difficulty supplying HEP to 24 coaches though,one would think.

I'm not sure what the maximum amount of HEP that an AEM-7 can put out actually is. However, there is also a finite limit on just how much HEP can be pushed through the 480 cables on the cars. This limit in fact prevents Amtrak from adding still more passenger carrying cars to the Auto Train than it currently runs with at peak times.

 

[jis]

Jis can you recommend any "YouTube" videos of the WAP7 hauling trains?

Here you go, not one but two side by side:

as it climbs the Gaya to Koderma ramp pulled by a WAP7.
Here is a picture of the Sealdah (Kolkata) Rajdhani pulled by a WAP4, mentioned in an earlier message in this thread.

And a picture of the Howrah (Kolkata) Rajdhani pulled by a WAP7. The markings on the engine says that it is from the Gomoh shed of East Central Railway, which it will pass on the way to Kolkata. The text on the side of the engine says in Hindi script "Bharatiya Rail" which means "Indian Railways".

These two trains depart New Delhi half hour apart every day, Sealdah one at 4:30pm and Howrah one at 5pm and travel pretty much 20 mins to half an hour apart over the entire distance of 900 miles to Kolkata in about 17 hour with about 6 or 7 stops on the way. On regular weekdays there are two other Rajdhanis that depart between these two and run on the same route for most of the way but then branch off to other destinations. So there are like 4 or 5 of these trains running 10 minutes apart for some 600 miles down that route each day.

 

[Rob_C]

I'm not sure what the maximum amount of HEP that an AEM-7 can put out actually is. However, there is also a finite limit on just how much HEP can be pushed through the 480 cables on the cars. This limit in fact prevents Amtrak from adding still more passenger carrying cars to the Auto Train than it currently runs with at peak times.

Wouldn't an extra P40 *between* the superliners and the autoracks solve that problem? The superliners would then get power from the front as well as the end of the consist?

 

[jis]

I'm not sure what the maximum amount of HEP that an AEM-7 can put out actually is. However, there is also a finite limit on just how much HEP can be pushed through the 480 cables on the cars. This limit in fact prevents Amtrak from adding still more passenger carrying cars to the Auto Train than it currently runs with at peak times.

Wouldn't an extra P40 *between* the superliners and the autoracks solve that problem? The superliners would then get power from the front as well as the end of the consist?

I am no expert on this subject. But I have heard/read postings by at least two conductors (one on MNRR and one on NJT), who regularly work on New York area commuter trains, which as you know are typically longer than most Amtrak trains, who stated that FRA does not allow sourcing HEP from multiple units for a single train, unless all HEP can be controlled from the engineer's position, whether it be in a locomotive or a cab control car. I don't know if that would be a barrier to making use of a second P40 as you suggest, but seems that it might. At present I don't think the control lines allow control of multiple HEP units, nor are the train-lines capable of being fed from multiple such simultaneously. But as I said I am no expert, and I am happy to be corrected if I am under the wrong impression.

 

[had8ley]

In all reality one of the motors is very rarely "along for the ride." They'd have to take the leader offline, and for the most part it's not very practical to do so. Rather than running in a cruising notch of 5 or 6 you're more likely to be in 3.

Maybe Dutch can clarify this but somewhere in the cob webs I seem to remember an FRA reg that stated that the lead unit HAS to be on line if it is running and operable.

 

[AlanB]

In all reality one of the motors is very rarely "along for the ride." They'd have to take the leader offline, and for the most part it's not very practical to do so. Rather than running in a cruising notch of 5 or 6 you're more likely to be in 3.

Maybe Dutch can clarify this but somewhere in the cob webs I seem to remember an FRA reg that stated that the lead unit HAS to be on line if it is running and operable.

Not unless that's a new rule.

Going back several years ago I was on a Silver Palm coming north with two units. All the sudden there was considerable heavy smoke coming from the second engine and we lost HEP. I'm guessing that the unit blew the rectifier stack, but I never heard the real reason. We ran for almost two hours till we reached a point where we could stop and allow the engineer to walk back to the second engine and flip some switches that would allow him to give us HEP from the lead engine.

I was so thankful that I wasn't on the sunny side of my Viewliner car, as it was much warmer across the hall by the time we got to the station and the HEP was restored.

And then, just two summer ago when the OTOL gang went west on the CZ, it was during one of the periods where we didn't go via Moffett. This got us into Salt Lake very early. Many of us had walked up to see the engines and take a few pictures. There were also a few kids up there too. The engineer saw all of us wandering around up there and came back from her car to chat with the kids and us. She could have been on her way home, but instead came back to talk with everyone and answer questions.

She pointed out, for those who hadn't already figured it out, that the lead engine was so quiet because it was shut down and the second engine was supplying HEP and was therefore much nosier.

 

[jis]

And then, just two summer ago when the OTOL gang went west on the CZ, it was during one of the periods where we didn't go via Moffett. This got us into Salt Lake very early. Many of us had walked up to see the engines and take a few pictures. There were also a few kids up there too. The engineer saw all of us wandering around up there and came back from her car to chat with the kids and us. She could have been on her way home, but instead came back to talk with everyone and answer questions.
She pointed out, for those who hadn't already figured it out, that the lead engine was so quiet because it was shut down and the second engine was supplying HEP and was therefore much nosier.

Yes, it was after having a long chat with her I came to the full realization about how wonderful the P42s are , even given all its warts here and there. She seemed to really enjoy operating those engines.

 

[ALC Rail Writer]

And then, just two summer ago when the OTOL gang went west on the CZ, it was during one of the periods where we didn't go via Moffett. This got us into Salt Lake very early. Many of us had walked up to see the engines and take a few pictures. There were also a few kids up there too. The engineer saw all of us wandering around up there and came back from her car to chat with the kids and us. She could have been on her way home, but instead came back to talk with everyone and answer questions.
She pointed out, for those who hadn't already figured it out, that the lead engine was so quiet because it was shut down and the second engine was supplying HEP and was therefore much nosier.

Yes, it was after having a long chat with her I came to the full realization about how wonderful the P42s are , even given all its warts here and there. She seemed to really enjoy operating those engines.

And that night in my roomette I prayed and I said "Thank you God for the blessings of this P42 you have bestowed upon us during this fine trip. Thank you, so much."

:lol:

 

[saxman]

The Eagle also did carry two motors at one point, IIRC. However, I think you have to go back to the late F-40 days, because a quick browse of P-42's in Texas only shows the Sunset carrying two motors...

Just clarification, the Texas Eagle was using two P-42's up at least until 2003. I remember seeing the news they were getting rid of one on the route just a few months after my trip on the TE which was in May. I have a picture of it somewhere in my stockpile with two locos.

 

[GG-1]

I'm not sure what the maximum amount of HEP that an AEM-7 can put out actually is. However, there is also a finite limit on just how much HEP can be pushed through the 480 cables on the cars. This limit in fact prevents Amtrak from adding still more passenger carrying cars to the Auto Train than it currently runs with at peak times.

Wouldn't an extra P40 *between* the superliners and the autoracks solve that problem? The superliners would then get power from the front as well as the end of the consist?

Aloha

This wold allow the "current" to be distributed but adds the issue of generator phase, which probably make the gains not worth the headache.

 

[Chris J.]

I'm not sure what the maximum amount of HEP that an AEM-7 can put out actually is. However, there is also a finite limit on just how much HEP can be pushed through the 480 cables on the cars. This limit in fact prevents Amtrak from adding still more passenger carrying cars to the Auto Train than it currently runs with at peak times.

Wouldn't an extra P40 *between* the superliners and the autoracks solve that problem? The superliners would then get power from the front as well as the end of the consist?

Aloha

This wold allow the "current" to be distributed but adds the issue of generator phase, which probably make the gains not worth the headache.

Is there any reason that all the HEP systems needs to be connected together? Could one stick some form of 'generator wagon' in there to produce HEP for some of the coaches, with the others being fed from the loco, but not connect the two HEP sets together.

 

[Ryan]

You would either need to man the car or devise some means of controlling the generator from the locomotive - neither of these is a particularly good solution.

 

[AlanB]

I'm not sure what the maximum amount of HEP that an AEM-7 can put out actually is. However, there is also a finite limit on just how much HEP can be pushed through the 480 cables on the cars. This limit in fact prevents Amtrak from adding still more passenger carrying cars to the Auto Train than it currently runs with at peak times.

Wouldn't an extra P40 *between* the superliners and the autoracks solve that problem? The superliners would then get power from the front as well as the end of the consist?

Aloha

This wold allow the "current" to be distributed but adds the issue of generator phase, which probably make the gains not worth the headache.

Is there any reason that all the HEP systems needs to be connected together? Could one stick some form of 'generator wagon' in there to produce HEP for some of the coaches, with the others being fed from the loco, but not connect the two HEP sets together.

In the case of the Auto Train example given, it is technically possible to short loop the 480 power cables halfway through the consist. That would avoid the phase problem mentioned by GG-1, since the lead engines would provide power to the front half of the train, while the engine in front of the auto racks would provide power to the rear half of the train. This would avoid the problem whereby the 480 cables can't carry anymore power than they do.

The problem with this rather simple solution is that as noted by Hokie, FRA regs require that the engineer must be able to control HEP for the entire train. In this case, or if one placed some type of power generation car in the middle, is that the engineer would not be in control of HEP for the entire train. The engineer would only have control over the HEP supplied by the front locos. This could lead to someone requesting that HEP be turned off to uncouple cars, having the engineer respond positively, and forgetting that the engineer doesn't control the entire train and getting electrocuted.

 

[Green Maned Lion]

In the case of the Auto Train example given, it is technically possible to short loop the 480 power cables halfway through the consist. That would avoid the phase problem mentioned by GG-1, since the lead engines would provide power to the front half of the train, while the engine in front of the auto racks would provide power to the rear half of the train. This would avoid the problem whereby the 480 cables can't carry anymore power than they do.
The problem with this rather simple solution is that as noted by Hokie, FRA regs require that the engineer must be able to control HEP for the entire train. In this case, or if one placed some type of power generation car in the middle, is that the engineer would not be in control of HEP for the entire train. The engineer would only have control over the HEP supplied by the front locos. This could lead to someone requesting that HEP be turned off to uncouple cars, having the engineer respond positively, and forgetting that the engineer doesn't control the entire train and getting electrocuted.

We have managed to develop MU cables that provide for controlling an entire second engine at the back of a train. I'm sure there is a simple way to run a control mechanism that would allow the engineer to control the HEP for a rear-located locomotive. Actually, it wouldn't surprise me if push-pull trains already have such a function.

 

[printman2000]

The problem with this rather simple solution is that as noted by Hokie, FRA regs require that the engineer must be able to control HEP for the entire train. I

Didn't they at one point use HEP power cars to run HEP on some trains? If so, how could the engineer control that? Or was that before the regs?

 

[VentureForth]

In the case of the Auto Train example given, it is technically possible to short loop the 480 power cables halfway through the consist. That would avoid the phase problem mentioned by GG-1, since the lead engines would provide power to the front half of the train, while the engine in front of the auto racks would provide power to the rear half of the train. This would avoid the problem whereby the 480 cables can't carry anymore power than they do.
The problem with this rather simple solution is that as noted by Hokie, FRA regs require that the engineer must be able to control HEP for the entire train. In this case, or if one placed some type of power generation car in the middle, is that the engineer would not be in control of HEP for the entire train. The engineer would only have control over the HEP supplied by the front locos. This could lead to someone requesting that HEP be turned off to uncouple cars, having the engineer respond positively, and forgetting that the engineer doesn't control the entire train and getting electrocuted.

I think I'm confused. I've never seen a loco between the coaches and the auto racks on the Auto Train...

 

[MattW]

Great Smokey Mountains Railroad I know uses a generator car, but it's a scenic Heritage Railroad so I'm sure they got an exception.