Western Railroad Discussion > Trains Magazine reporting New BNSF EMD order

Trains Magazine is reporting that BNSF has ordered 10 SD70ACe-P4 locomotives which is EMD's answer to the GE ES44C4, but with a difference, the EMD locomotives will feature a B1-1B wheel arrangement.



Edited 1 time(s). Last edit at 01/25/12 10:03 by SOO6617.

How is that possible, and is there at least a drawing of these?

Seems a little odd if they intend to do the same weight-transfer thing as the GEs do when they're loading. I'd assume they're not going with any sort of weight transfer mechanism, or they've got some really wild truck designs we haven't seen yet.

Two powered axles plus 1 idler axle in each truck, right? I suppose that's possible, but why?

lowwater Wrote:
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> Two powered axles plus 1 idler axle in each truck,
> right? I suppose that's possible, but why?

Same reason GE did it, lower price, and replace DC motored models.

NDHolmes Wrote:
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> Seems a little odd if they intend to do the same
> weight-transfer thing as the GEs do when they're
> loading. I'd assume they're not going with any
> sort of weight transfer mechanism, or they've got
> some really wild truck designs we haven't seen
> yet.

With EMD's proven radial trucks u really don't need the weight-transfer gagdet because the extra traction is already there.

What?!? Crazy! However, aren't there some export B-B truck engines out there already? Brazil, maybe?

- Jeff

spinecar Wrote:
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> NDHolmes Wrote:
> --------------------------------------------------
> -----
> > Seems a little odd if they intend to do the
> same
> > weight-transfer thing as the GEs do when
> they're
> > loading. I'd assume they're not going with any
> > sort of weight transfer mechanism, or they've
> got
> > some really wild truck designs we haven't seen
> > yet.
>
> With EMD's proven radial trucks u really don't
> need the weight-transfer gagdet because the extra
> traction is already there.


I re-read the post. Will these be 8-axle locos with 4 powered axles?

spinecar Wrote:
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> I re-read the post. Will these be 8-axle locos
> with 4 powered axles?

Standard six axles, only four powered. Just like the C4s, except rather than A1A trucks (front and back powered, center's an idler) these will be a B1 or 1B arrangement, meaning the two powered axles are together on each truck and the idler is at one end. Still six axle overall.

Presumably the motive power department likes the C4s, since they're asking EMD to make a similar critter. That said, any of you guys that run them - how do you like them now that they've been in service for a while?

They don't ride any different then a 6 motor locomotive. The only train we had one on in the lead had so much power on it we didn't work it hard enough to go to C4 mode.

Regards
Q-GP30

Indian Railways:

WDG-4 EMD 16-710G3B GT46MAC Co-Co
WDP-4 EMD 16-710G3B GT46PAC Bo1-1Bo

Indian Railways has been using Bo1-1Bo WDP-4 GT46PAC locomotives, with four rather than six traction motors, in passenger service since 2001.

NDHolmes Wrote:

> Standard six axles, only four powered. Just like
> the C4s, except rather than A1A trucks (front and
> back powered, center's an idler) these will be a
> B1 or 1B arrangement, meaning the two powered
> axles are together on each truck and the idler is
> at one end. Still six axle overall.

Strangely enough, such an arrangement won't be a first on Santa Fe rails. The 1935 Super Chief boxcabs, built as B-B's, were rebuilt in 1938 in the company shops into turret-cabs 1 and 10 with a 1B-B five-axle wheel arrangement, and a year later they were modified again to a 6-axle, 4-powered, 1B-1B wheel arrangement.

http://www.northeast.railfan.net/images/tr_sf1.jpg

Of course, they had DC traction motors and no axle-lifting gizmo - the idea was apparently to add a "pilot axle" to get the locomotives to track better at speed. The 1L lasted in this configuration until it was retired in 1953.

I would think a 1B rather than B1 arrangement would be preferable on the lead truck, as the non-powered axle, assuming it has the usual axle load, would act as a "rail conditioner" for the leading powered axle. Of course with AC there should be less of a tendency to lose adhesion, but still....

Regarding the ATSF 1B truck from the late thirties: It was my understanding from an article in a then-contemporary 'Railway Age' that the Santa Fe was also concerned about what might happen if a powered leading axle were to lock up at speed.

Best, SZ

BNSF quit ordering the radials, so it will be interesting to see this critter.
The AC four motor will pull the same as a 6 motor DC unit they say.
I have put a C4 to the test. Started it on a hill pretty hard, 100k and she lifted the center axle and stopped shaking. Off we went. No fuss no muss.
Amtrak34east uses them to load coal and he has no complaints that I have heard.

Is that EMD demo on the eastern board the critter in question?

I was hoping they would tack a order for 80MACs on the rear of the Brazil order.

And if the leading wheel is an idler, they may have to move the centerpin I would think. I would think the A1A would help in the "wrapup" of the truck.

And UP has been modifying SD70M's and SD90MAC's so the truck are no longer radial iirc.

Bill Miller
Galt, ON

CCMF Wrote:
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> And UP has been modifying SD70M's and SD90MAC's so
> the truck are no longer radial iirc.

Negative they removed a useless piece of the mechanism EMD has deemed unnecessary to help on maintence of the truck. They are still radial

Brett

Trains Mag has an extended discussion on your topic in their forums as I'm sure you are aware being you posted this. For those of you who want more indepth info you should check it out. Very interesting. Thanks for bringing this topic up.

So will these units have completely different trucks? Does anyone know? Or will they just be like GE C4s with an extra set of brake cylinders?

Posted from iPhone

SD45X Wrote:
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> I was hoping they would tack a order for 80MACs on
> the rear of the Brazil order.


I hope they're not in a hurry for them....

http://www.lfpress.com/news/london/2012/01/25/19291636.html


- Dave

thb403 Wrote:
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I hope they're not in a hurry for them....
>
> http://www.lfpress.com/news/london/2012/01/25/1929
> 1636.html

You assume they are being built in London. There are three plants: London, Muncie, Bombardier Mexico.



Edited 1 time(s). Last edit at 01/26/12 07:38 by alamode.