WHICH ENGINE IS BETTER

[frj1983]

I'm not entirely sure, but they were new and in the newest paint scheme. I would probably guess AC4400's since AC is the general loco used on coal drags. The detector read out 612 axles which would mean 2 6 axle locos and 250 4 axle coal cars, which seemed to be the standard consist for the constant parade of coal trains that came through. The length also makes me thin AC because a DC would have a hard time getting the consist underway without overheating the traction motors.

I think you mean 150 4-axle coal cars! 250 would be a train over two miles long and certainly wouldn't be able to be pulled (even empty, probably) by two locomotives. I have heard of some two-mile-long trains running on the BNSF Transcon (can't remember if they're stack trains or unit trains), but those top out at 10,000' (250 would be 12,500') and have serious power (including DP--dual power--pushing from the back). Plus, the math works better with 150 cars...

I'm not even sure I'd believe two motors pulling 150 cars--the Alaska Railroad uses four SD70MACs (providing 16,000 hp) in a dual-power configuration to move a 100-car freight train over grades that are probably less than what CSX sees (and certainly less than what BNSF and UP see out west). Unless they're empties and on relatively flat ground, I'm not sure that any two six-axled locomotives--even two 6,250-hp SD90MACs, which CSX never had, or the 6,250-hp GE AC6000CW or the 5,000-hp SD80MACs, which they do--could handle 150 cars.

Is it possible there are more engines, including pushing from the back that one may not notice when first looking at the train coming by? Four six-axle engines and 147 cars would be much more believable for me...

Lately,

I've noticed the BNSF running approximately 150 car coal trains with 2 SD70macs pulling in front and one pushing behind all the cars. They move pretty smoothly along!

 

[battalion51]

It would be my belief that if DPU's were needed they'd only be on in areas where you've got grades to deal with. If you're out in the plains with relatively flat running, why use a DPU?

 

[jackal]

It would be my belief that if DPU's were needed they'd only be on in areas where you've got grades to deal with. If you're out in the plains with relatively flat running, why use a DPU?

Applying 16,000 hp acceleration to a 15,000-ton train would almost certainly break a knuckle. The Alaska Railroad has a rule that even if four SD70MACs are on the head-end, only three can be online at any given time precisely because of this. They put all four in the front (with three online) on the northbound empties and then do DP on the southbound loads.

On flat land, three (two pulling and one pushing, as frj1983 described) would probably work fine. Acceleration might be a little sluggish, but fuel and equipment savings may make it worthwhile. Two pulling alone...I don't know. Maybe pulling from DEN to CHI, which is a long, gentle downhill slope!