When IAIS first got their new engines, they occasionally employed a pusher engine at the rear of a train. I can’t remember the last time I saw a train configured this way. Can anyone shed light on this apparent change in motive-power strategy?
I don’t know anything about IAIS’s motive power strategy, but BNSF uses alot of pusher engines on their loaded coal trains across southern Iowa. Other BNSF trains don’t always have a pusher, but loaded coal trains usually have two engines on the front and one in back.
Distributed power for longer trains and better power distribution. A feature of the new locomotives, in use since they were delivered in 2009.
Mentioned in article in Trains, September 2010. Also see this thread from a few years ago on this forum: http://cs.trains.com/trn/f/111/t/150275.aspx
These are not “pushers”, This is “Distributed Power” and it is all controlled by the one engineer at the front of the train. It saves a lot of wear on the cars and on the tracks, and really improves train control.
Two in front one in back is normal on the coal trains through here.
Oil trains usually do not have a locomotive in the back since that would require another spacer car. I’m not sure that they allow oilcans to be pushed.
ROAR
Around these parts, the oil trains are about the only things that regularly do have DPUs. They do have another spacer car on the rear.
Soooo… whut’s the difference between “Pushers” and “Distributed Power”?
A pusher has at least an engineer on board; A DPU is controlled by the engineer at the head end.
Here is a link to an empty oil cans train in Pepin, WI with two engines leading, a spacer car and a spacer car and a DPU engine on the rear.
I don’t get to see the IAIS very often, but I follow the IAIS group on yahoo. It seems I hear about reports of trains with a DP. Especially when their keeping track of the heritage unit. Every train may not use a DP or they may be reconfiguring the engine consists at Silvis or South Amana, so that a train may only be DP for part of it’s journey.
Jeff
I remember a railfan visit to Marengo, Iowa last Spring as I ‘imaged’ a train going to Des Moines. At Marengo I watched an IAIS crew either drop off and/or collect cars. These movements required the train to be backed into a siding.
I’m sure there are multiple customers that are serviced by the through-trains passing by their town. It makes sense to switch out cars this way instead of sending a switcher from a distant yard, if that can be avoided.
It occurs to me that if there is a DPU on the end of the train, disconnecting the DPU at each customer’s siding would add up to a big hassle.
Maybe they decided it wasn’t worth the added time-on-track, or other considerations, to go with a DPU. Like I say, I cannot remember the last time I saw a DPU on IAIS.
A DPU unit would not have to be physically cut off the train to perform a pick up on set off. The Engineer controlling the train has the ability to cut off response of the DPU when it doesn’t suit the job to be performed.
Thanks for the response-
So, what I’m saying is that it might be a pain for crews to disconnect the DPU every time the through-train, which is also required to act as a switcher, needs to service a local shipper. They would have to disconnect the DPU from the train, and then back into a siding for those cars to be dropped off or picked up, then re-connect the DPU.
I surmise the DPU can be deactivated by the lead unit engineer via electronic signal, so my supposition is that it matters not if the cars to be deposited or collected is within the train or at the end of the train, but it is still a hassle to disconnect and reconnect the DPU, even if a little.
If the train is actually classified as a true run-through train without local stops, why then not utilize a DPU? IAIS is an average lower RR speed with fewer car movements vs BNSF & UP et. al., so maybe DPU is not as cost effective for IAIS, comparatively. TRAINS mag. had an article describing the benefits of the DPU on reducing track wear and coupler damage, I found this to be interesting and informative.
Like I say, I can’t remember the last time I saw a DPU on IAIS, and still looking for insight as to why. IAIS is a versatile organization, perhaps they listen to the people who work for them.
Talk to me, I want to understand.
Thank you Trains mag. for adding spellcheck.