On Union Pacific coal trains passing through on the former C&NW in the Chicago area, I’ve noticed some unit coal trains to/from Powder River have rear-end pushers (UP & former SP AC4400’s), but I haven’t had a chance to notice whether there is any set pattern as to which particular coal trains have these pushers. I saw an eastbound with two AC4400’s on the front and one pushing (Wisconsin Electric - older series gons from 70’s or 80’s). The train had approx. 125 loads, and these cars are rated at a max. load of 211,000 lbs. apiece, for an approximate train weight of 13,200 tons (which two AC4400’s could easily handle on the relatively flat terrain of the former CNW east of Council Bluffs).
Most of the Wisconsin Electric trains with the aluminum cars will have a DPU (Distributed Power Unit) on the rear…I’m a little surprised to hear about one on the train with the older cars.
Having the rear-end unit enables the railroad to lengthen the train (110 cars is about normal for a coal rain without the DPU; the DPU-equipped WEPX trains are generally around 130-135 cars). Gross weight per car is 143 tons, so we’re getting up there in total weight. The big advantage of the unit on the rear is in train handling…a brake application is initiated from both ends of the train, so it takes half the time for all brakes to be set. Releases would also be quicker.
WEPX trains are the most likely ones to have the DPU on the rear. I’ve seen one of the Sheboygan trains with a rear unit (EDGX cars), and a couple of ComEd (CWEX) trains. So they’re getting a little more common.
I haven’t seen any so far on trains that go off-line (NORX, CIPX, DEEX, etc.).
What’s neat is to be watching at Park (Elmhurst) when an empty train with a DPU on the rear heads out. The engineer knows his length, so he knows when the train’s clear of the interlocking, and when to open up. To see the rear unit lean into 'em just as he’s clearing the switches, and realize that there’s nobody in there, has to make you go “Wow!”[^]
We watch loaded coal trains going south out of Lincoln with the DPU on the end. Just as they clear the last crossing at the east end of the yard (right where we sit), that unit always powers up and it is so spooky, seeing an empty cab and hearing it going to the next level.
Another question - some of the coal trains have had only one AC4400 up front with a single DPU AC4400 on the rear (I believe I saw an SD9043 DPU on one occasion. Has anyone been seeing this combination lately? I would image it fits the category described by CShave above (approx. 110 cars - better train handling compared to having both units up front, and only for WEPX or ComEd (online) destinations).
Mr. Frank-
I saw that exact combination a few weeks ago at the Pleasant Prairie power plant (WEPX). It was strange seeing the train start moving without ANY slack action. It just started moving nearly silently (with just a few groans) like it was one solid piece of equipment.
I live in Kenosha (right by WEPX power plant)- about 3/4 of the coal runs we get through here have DPU. Once saw a Sheboygan (EDGX) coal run with a CNW AC44 on the fron and UP AC6000 pushing- just two engines, but it was flying. BTW, that happened in April
I’ve noticed BNSF doesn’t put pushers on the end of trains with any kind of flat cars (bulkheads, wellcars, spinecars, or even centerbeams). I’m gonna guess that this is because flatcars are not as structurally stong as other types of rail cars? Is it because of some of these articulated intermodel cars? Or because some have drawbars connecting them instead of couplers? Could a pusher cause a flat car to flip up in the air in the event of an accident or even under normal circumstances? I remember reading in a Trains ariticle that some railroads wouldn’t put pushers behind a caboose because the caboose wasn’t as strong framed as other cars and the crew could be crushed.
BNSF used to put pushers on the end of intermodel freights 3 years ago but have stopped this practice (at least through Kansas, anyway). I’ve also noticed that pushers aren’t present on the ends of vehicle trains. Is if for the same reasons? Are autoracks just essentially multilevel flat cars?
Does anybody have any idea what I’m talking about?
Yes! Yes! Yes! - I have asked part of this question before and gotten some pretty mystified answers! Freight thru here is always with at least two units on the front. Coal has them usually front and back - especially if going south out of here.
But your statement about some having drawbars connecting them instead of couplers is what my question was about! You answered that one w/o even knowing it! I am so glad someone else has seen it too!
Now we will wait together for the rest of the answers!
when i worked the pusher service we shoved everything that was over weight. that is the key to it. if the freight is not over weight it dont need a push. coal trains are usually running in the 13,000 - 16,000 ton range. 2 engines wont handle this up hill. now back to the question. when pushing certain trains you made sure you didnt put the rear in a bind, auto racks have long cushion drawbars and depending where we was i would drop a notch of power to keep from binding these cars more. the solid draw bar cars is not a problem nor any strack train. they push easy. grain cars push easy auto racks are the worse and they just pop and jar…
as far as a pusher kicking a car out , yes it can be done but not likly. while pushing everything is in thery going the same way speed power the rear is just assisting. now lets say you go into emergency on the head end and brake pipe is not cut in on the pusher it will keep on pushing til it comes off the tracks to. a maned pusher and distributed power works the same just how its done is differant.
one last note on some of those bnsf coal trains where they dump has alot to do with the power, its one long track that ends the loop was out of service. so the power that pushed is now the lead back…
(1) Have seen the following on a regular basis in the Denver area on UP: 2 engines in lead consist, 3 dpu units 2/3rds of the way back and one or two dpu units on the rear with up to 140+ coal cars
(2) You are not going to push on empty spines or flatcars because if you do, you risk running a slack action derailment where those light cars pop up off the rail when the slack runs -in, especially with the use of an emergency application. Simple physics can create quite a mess which the ATSF side of the BNSF family tree had learned on multiple occasions on Raton Pass, Cajon Pass, Rustler Springs, Carlsbad and a few other places in the RCE days (1980’s)…the application of the brake pipe on the remote on the middle or rear units is not always as “instant” as it ought to be. There is a slight lag in the reaction time on the remote engines and the air passing through the triple valve brake lines on that long of a train.
The heaveir a train gets the more difficult it becomes to power it from the front end especially when going up and down hills. The weight of the train some times exceeds the tensile strength in the draw bars in the cars directly behind the power units. To much slack action and you pull the drawbar apart. Both the UP and BNSF use multiple DPU’s in the mountains and in hilly teritory to avoid this problem. A lot of the time you will see a DPU in a train out on the flat lands that came from the mountains or hilly country simply because it is easier to run it though than to send out a crew to bring it back to a terminal
On Union Pacific coal trains passing through on the former C&NW in the Chicago area, I’ve noticed some unit coal trains to/from Powder River have rear-end pushers (UP & former SP AC4400’s), but I haven’t had a chance to notice whether there is any set pattern as to which particular coal trains have these pushers. I saw an eastbound with two AC4400’s on the front and one pushing (Wisconsin Electric - older series gons from 70’s or 80’s). The train had approx. 125 loads, and these cars are rated at a max. load of 211,000 lbs. apiece, for an approximate train weight of 13,200 tons (which two AC4400’s could easily handle on the relatively flat terrain of the former CNW east of Council Bluffs).
Most of the Wisconsin Electric trains with the aluminum cars will have a DPU (Distributed Power Unit) on the rear…I’m a little surprised to hear about one on the train with the older cars.
Having the rear-end unit enables the railroad to lengthen the train (110 cars is about normal for a coal rain without the DPU; the DPU-equipped WEPX trains are generally around 130-135 cars). Gross weight per car is 143 tons, so we’re getting up there in total weight. The big advantage of the unit on the rear is in train handling…a brake application is initiated from both ends of the train, so it takes half the time for all brakes to be set. Releases would also be quicker.
WEPX trains are the most likely ones to have the DPU on the rear. I’ve seen one of the Sheboygan trains with a rear unit (EDGX cars), and a couple of ComEd (CWEX) trains. So they’re getting a little more common.
I haven’t seen any so far on trains that go off-line (NORX, CIPX, DEEX, etc.).
What’s neat is to be watching at Park (Elmhurst) when an empty train with a DPU on the rear heads out. The engineer knows his length, so he knows when the train’s clear of the interlocking, and when to open up. To see the rear unit lean into 'em just as he’s clearing the switches, and realize that there’s nobody in there, has to make you go “Wow!”[^]
We watch loaded coal trains going south out of Lincoln with the DPU on the end. Just as they clear the last crossing at the east end of the yard (right where we sit), that unit always powers up and it is so spooky, seeing an empty cab and hearing it going to the next level.
Another question - some of the coal trains have had only one AC4400 up front with a single DPU AC4400 on the rear (I believe I saw an SD9043 DPU on one occasion. Has anyone been seeing this combination lately? I would image it fits the category described by CShave above (approx. 110 cars - better train handling compared to having both units up front, and only for WEPX or ComEd (online) destinations).
Mr. Frank-
I saw that exact combination a few weeks ago at the Pleasant Prairie power plant (WEPX). It was strange seeing the train start moving without ANY slack action. It just started moving nearly silently (with just a few groans) like it was one solid piece of equipment.
I live in Kenosha (right by WEPX power plant)- about 3/4 of the coal runs we get through here have DPU. Once saw a Sheboygan (EDGX) coal run with a CNW AC44 on the fron and UP AC6000 pushing- just two engines, but it was flying. BTW, that happened in April
I’ve noticed BNSF doesn’t put pushers on the end of trains with any kind of flat cars (bulkheads, wellcars, spinecars, or even centerbeams). I’m gonna guess that this is because flatcars are not as structurally stong as other types of rail cars? Is it because of some of these articulated intermodel cars? Or because some have drawbars connecting them instead of couplers? Could a pusher cause a flat car to flip up in the air in the event of an accident or even under normal circumstances? I remember reading in a Trains ariticle that some railroads wouldn’t put pushers behind a caboose because the caboose wasn’t as strong framed as other cars and the crew could be crushed.
BNSF used to put pushers on the end of intermodel freights 3 years ago but have stopped this practice (at least through Kansas, anyway). I’ve also noticed that pushers aren’t present on the ends of vehicle trains. Is if for the same reasons? Are autoracks just essentially multilevel flat cars?
Does anybody have any idea what I’m talking about?
Yes! Yes! Yes! - I have asked part of this question before and gotten some pretty mystified answers! Freight thru here is always with at least two units on the front. Coal has them usually front and back - especially if going south out of here.
But your statement about some having drawbars connecting them instead of couplers is what my question was about! You answered that one w/o even knowing it! I am so glad someone else has seen it too!
Now we will wait together for the rest of the answers!