Locomotive duties

[URI]

Was looking at BNSF SD70ace pics, and I noticed that these units almost always seem to be pulling coal? Same with the Macs. Anyone here no more to the story than I? I ask because I hear Kato will be making these in BNSF colors. They interest me.

 

[jbaakko]

BNSF uses the AC4400's, SD70MAC's & SD70ACe's in coal drags because of the slow speed "drag" traction they develop. As far as BNSF's concerned, they're more suited for this then DC traction.

 

[MRLdave]

Up here in Montana, the primary power seems to be Dash8's and 9's, with a few MAC's in the mix. 70ACe's seem pretty rare, but that may be due to the problem they suffer up here.MRL has constant problems with their ACe's and tunnels and I'd guess the BNSF's are no different. It seems the air filters,cab filters, ect. don't like breathing the smoke in the tunnels. In bad cases, the crews have to use masks and worse case, the carbon in the smoke starts to short out the electronics. Josh is correct about the AC units having better "drag".

 

[URI]

Is coal the only "drag" train, or is unit grain trains considered in this catagory? Great info, thanks.

 

[jbaakko]

I'm not sure, I've seen BNSF MAC's on a head end of Intermodal, and grain occasionally, though I know they traditionally use them on coal.

 

[MRLdave]

I see a fair number of the executive scheme MAC's come thru Montana, plus a few heritage 3 paint jobs. They appear on any BNSF train that comes thru.....usually 3 or 4 engines depending on the load....2 on the front and one or 2 on the back. They put the MRL helpers in the middle over the passes. Lots of grain and coal unit trains, plus intermodal.

 

[URI]

Thanks again for all the info, should be ok then to drop a pair of AC44's then on a grain unit without looking so out of place. Still hope Kato makes the ACE in BNSF. I'd really like to upgrade my roster with some modern power.

 

[bnsf971]

Is coal the only "drag" train, or is unit grain trains considered in this catagory? Great info, thanks.

You can make a GM train a "drag" as well. A tank train could be a drag, but not Intermodal.

 

[TrainMaster1]

"Drag" trains come in many varieties although minerals seem to be most common. Grain would certainly work as would a heavy manifest. Intermodals are generally overpowered per ton in order for them to maintain a faster schedule. The real benefit of AC is that you do not have to worry about the traction motors overheating and burning out like you do with DC. Most DC motors have a continuous service rating (MPH) that the units have to maintain under load. The hours of service meter lets the engineer know when they are in the red zone. This is okay for a short time but eventually will destroy a DC Motor if left unchecked. An AC motor on the other hand does not face this same constraint and therefore is better suited to slow speeds and heavy trains for a far longer period of time. Both types of engines are used in fast and drag service past our house in PA.

Nick
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