Passenger Trains > Auto Train question.

I have a question. Watching and fanning when you see an Amtrak trian say 5 6 cars you see a single engine up front and more than that like 5,6,3,4, etc you see 2 with up to 9-10 cars and if theres more you sometimes see 3 up front. So Im watching the auto train for the umpteenth time and I keep wondering why with 20 superliner cars and 19-20 car carriers with sutomibiles how they manage with just 2 p42's . Are these upgraded to bigger prime movers because I think the where only 2800hp or so origianlly. Just wondering why there  isnt more power , I would think they would need at least 8000+ Hp to move this mass with any speed . Am I missing something in how they calcultae power? Thanks



Edited 2 time(s). Last edit at 04/01/20 09:05 by kingman.

kingman Wrote:
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> I have a question. Watching and fanning when you
> see an Amtrak trian say 5 6 cars you see a single
> engine up front and more than that like 5,6,3,4,
> etc you see 2 with up to 9-10 cars and if theres
> more you sometimes see 3 up front. So Im watching
> the auto train for the umpteenth time and I keep
> wondering why with 20 superliner cars and 19-20
> car carriers with sutomibiles how they manage with
> just 2 p42's . Are these upgraded to bigger prime
> movers because I think the where only 2800hp or so
> origianlly. Just wondering why there  isnt more
> power , I would think they would need at least
> 8000+ Hp to move this mass with any speed . Am I
> missing something in how they calcultae power?
> Thanks

The P42DC's put out 4200 HP each unless they are providing HEP and then derate down to 3200 HP. Only one unit provides HEP so a two unit consist would be making  7400 HP.
And the Autotrain route doesn't have any major grades to deal with either.

Yes, you are not taking into account track gradients -- 52/53 basically follow the tidewater up the east coast.  Very few grades to worry about.

kingman Wrote:
-------------------------------------------------------
> I have a question. Watching and fanning when you
> see an Amtrak trian say 5 6 cars you see a single
> engine up front and more than that like 5,6,3,4,
> etc you see 2 with up to 9-10 cars and if theres
> more you sometimes see 3 up front. So Im watching
> the auto train for the umpteenth time and I keep
> wondering why with 20 superliner cars and 19-20
> car carriers with sutomibiles how they manage with
> just 2 p42's . Are these upgraded to bigger prime
> movers because I think the where only 2800hp or so
> origianlly. Just wondering why there  isnt more
> power , I would think they would need at least
> 8000+ Hp to move this mass with any speed . Am I
> missing something in how they calcultae power?


P42 - 4250 HP

TAW

Auto Train is limited to 70 mph and makes only one scheduled stop en route at Florence, S.C.  to refuel and recrew.  Except for tight lock couplers, the dynamics are similar to operating a 3,000 foot intermodal with two locomotives.  

It does take a while for the train to achieve 70 mph, though. This isn't a rocket ship. And doesn't need to be.

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jaybest Wrote:
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> Auto Train is limited to 70 mph and makes only one
> scheduled stop en route at Florence, S.C.  to
> refuel and recrew.  Except for tight lock
> couplers, the dynamics are similar to operating a
> 3,000 foot intermodal with two locomotives.  

No they are not.  Not even a rack train, as AT's brakes grab much better than that.

KV1guy knows best. 52/53 don't have mountains to cross, granted, but north of Pee Dee the route is not all mirror-flat. Also there are many single-track segments, so 52/53 have to contend with meets and the speed-ups/slow-downs they require. 

ctillnc Wrote:
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> KV1guy knows best. 52/53 don't have mountains to cross, granted, but north of Pee Dee the route is not all mirror-flat. Also there are many single-track segments, so 52/53 have to contend with meets and the speed-ups/slow-downs they require. 

All the comments sound good.  In addition, any idea how much padding is in the schedule?

Brian
 

The Auto Train locos are P-40's, not P-42's.  They are a dedicated fleet of 6 locos; P-40's because the engineers prefer the of air vs. electronic brake actuation and release for smoother train handling (direct quote from a road foreman). They are fully maintained and inspected by the Sanford shop crew. On rare occasions a P-42 may appear, usually as a third unit being ferried between Hialeah and Ivy City. 

> how much padding is in the schedule?

Occasionally it runs 1 hour faster than schedule. Recently the fastest I've seen is 1:15 faster than schedule, but I suspect it has done better. 

ctillnc Wrote:
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> > how much padding is in the schedule?
>
> Occasionally it runs 1 hour faster than schedule.
> Recently the fastest I've seen is 1:15 faster than
> schedule, but I suspect it has done better. 

In my experience, weekend trips tend to run a little faster than sched, so 75-90 minutes isn't out of the question. I think the CSX dispatching has become much more friendly in recent months, maybe the last year and a half.

ctillnc Wrote:
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> > how much padding is in the schedule?
>
> Occasionally it runs 1 hour faster than schedule.
> Recently the fastest I've seen is 1:15 faster than
> schedule, but I suspect it has done better. 

Amtrak typically uses 8% recovery time. For a 17h29m schedule, 8% is 1h18m, so that figure is about right.

TAW

I saw a video on youtube a few years ago of the Auto Train running with a single unit.

I would not have believed it had I not seen it myself.



Edited 1 time(s). Last edit at 04/02/20 05:38 by restricted_speed.

The AT does take some time to get up to speed. Here's a video I shot of it a few weeks ago departing from a standstill out of Lorton after the auto carriers were attached...
https://youtu.be/OjL3s6QSYGQ



Edited 1 time(s). Last edit at 04/02/20 08:51 by chasej.

Proves nothing. As long as any part of his train is still on the spur, he's only allowed rerstricted speed, 15 or 20 mph depending on the TT.

PRR1361 Wrote:
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> Proves nothing. As long as any part of his train
> is still on the spur, he's only allowed
> rerstricted speed, 15 or 20 mph depending on the
> TT.

And that only if the spur is good for anything over 10......CSX auxiliary tracks are almost ALWAYS 10mph...if Amtrak maintains the spur it might be good for more but they too aren't going lavish money on what amounts to a yard track. 

jaybest Wrote:
-------------------------------------------------------
> Auto Train is limited to 70 mph and makes only one
> scheduled stop en route at Florence, S.C.  to
> refuel and recrew.  Except for tight lock
> couplers, the dynamics are similar to operating a
> 3,000 foot intermodal with two locomotives.  

But like at Lorton and Sanford, isn't it a refuel, recrew, and move it out, and if early that's ok!!! Or does the train wait for a specific time to depart. 

I have seen the Auto Train depart as much as an hour early. It's reservation only and there is a hard stop for accepting cars at 3:30 so it's easy to do.

I've been on AutoTrain and watched the gate turn away late arrivals.

The train routinely shoves off btw 3.20 and 3.45.

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