Model Railroading > Push / Pull modeling

I solicited comments on the Eastern board about P / P operations , got some good comments, my reason was I like to reverse move into sidings but was experiencing derail's, models seem to like being pulled, so my ops now will be with a DPU, Ed

Ed Stewart
Jacksonville, FL

Are you using body mounted couplers? If not, that may be the problem when doing this with truck mounted couplers. Proper NMRA weighting of the cars would be important also.

Mike



Edited 1 time(s). Last edit at 09/03/14 05:03 by unclebob.

Thanks Mike, most are new cars with body mounts,

Ed Stewart
Jacksonville, FL

Generally speaking, your track work needs to be pretty much impeccable if you decide to do push/pull operating.

I'm going to assume that you wish to run commuter trains in push/pull operation. You'll want the biggest turnouts your space will allow, less lateral forces on the trucks. Proper weighting of all of the cars, maybe even a little heavier than NMRA specs.

I've shoved full size (21 real feet) trains around my RR, 36" min radius curves an grades of up to 4% and I don't have any issues.

Eric

Backing into a siding in prototype operations is a horrible mess. The train backing in has to have authority beyond the siding being used so the opposing train has to be held back a station. This creates a lot of extra paper work in track warrant territory and needs a train order operator at one or both stations to do it with trainorders. In CTC the dispatcher needs to stay with the trains making the meet to line switches and clear signals. He cannot be thinking elsewhere during the operation. So backing into sidings is an extremely rare prototype operation.

Posted from Windows Phone OS 7

Your comment about DPU operation presents another modeling question? Do you consist the DPU with your lead locos? That would be prototypical but a nightmare for modeling (dirty track, shorts, speed matching) Having a second operator is not true DPU operation. With Digitrax, you could run two consists on one throttle, but even that could be a headache for one operator.

-Sean

bigmc83 Wrote:
-------------------------------------------------------
> Your comment about DPU operation presents another
> modeling question? Do you consist the DPU with
> your lead locos? That would be prototypical but a
> nightmare for modeling (dirty track, shorts, speed
> matching) Having a second operator is not true
> DPU operation. With Digitrax, you could run two
> consists on one throttle, but even that could be a
> headache for one operator.
>
> -Sean

Isn't this the truth! From time-to-time I will try to do this on my N scale DC layout and, while it can work given perfect speed matching of locos, I end up holding my breath the whole time. One little loco stutter and the train is on the ground. I decided it's generally not worth the stress. That said, I've wondered if one could modify a loco so that maybe only one or two axles were driven so that it still provided a little helper power but a stutter with that loco resulted in less braking, and it would not push as hard if the head end stuttered.

fbe Wrote:
-------------------------------------------------------
> Backing into a siding in prototype operations is a
> horrible mess. The train backing in has to have
> authority beyond the siding being used so the
> opposing train has to be held back a station. This
> creates a lot of extra paper work in track warrant
> territory and needs a train order operator at one
> or both stations to do it with trainorders. In CTC
> the dispatcher needs to stay with the trains
> making the meet to line switches and clear
> signals. He cannot be thinking elsewhere during
> the operation. So backing into sidings is an
> extremely rare prototype operation.
>
> Posted from Windows Phone OS 7

Don't forget someone has to protect the shove as well. Sure the CO could drop off and pull the train by but then has to walk ahead again.

Posted from iPhone

Backing OUT of a siding can be efficient and save time.
Rather than send a short train through a mile or more of 10 MPH track and line out the other end, crews would line themselves into the close end of a siding, then line the switch back for the main line. After the opposing train passes, that same crewman can line them out, they shove back onto the main, crew lines for the main line and they take off at track speed. Can be made to work with TWC by granting authority after the passage of the opposing train.
But it takes a little more imagination and intellectual attention than many new railroaders seem to have.

Yes, shoving out of the siding after a meet with a short trains works very well especially if handlining switches is involved.

I agree with using after arrival authority in TWC. You just can't get dispatchers to issue them. When I started railroading in 1969 we could leave Alberton for Avery with three trains to meet on the way. Now where was a direct meet order ever issued. It was all has rights over, wait at until an after arrival of orders. It worked really well given there was no radio contract with the dispatcher for 100 miles and only one operator part of the day at Haugan.

Posted from Windows Phone OS 7

bigmc83 Wrote:
-------------------------------------------------------
> Your comment about DPU operation presents another
> modeling question? Do you consist the DPU with
> your lead locos? That would be prototypical but a
> nightmare for modeling (dirty track, shorts, speed
> matching) Having a second operator is not true
> DPU operation. With Digitrax, you could run two
> consists on one throttle, but even that could be a
> headache for one operator.
>
> -Sean

Yes I do DPU with the lead unit (single unit)

Ed Stewart
Jacksonville, FL

Models with body mounted Kadee couplers, good wheels and weight, can be pushed just as well as they can be pulled. But it's important that your cars meet some basic standards as far as weight, coupler height, swing, pin height, wheel gauge, truck swing and rock, free-rolling, and wheel clearance. When I was young, I skipped on these standards and suffered the typical fate of constant derailments, coupler slip aparts, and all the other maladies of sub standard rolling stock. With time I learned that investment in time and money upgrading your rolling stock to standards benefits me greatly in both trouble free operations and enjoyment of the hobby. It really pains me to see someone come to the club with equipment that is sub standard and then spend all day re-railing and putting their train back together. They usually go home pissed off at their equipment. Really the key to enjoying this hobby is quality equipment.

Ted Curphey
Ontario, OR

I think it was an operating session in Bakersfield CA years ago where I learned the trick of installing a long-shank coupler on one end of every Bombardier car to prevent the diaphragms from touching in push-mode. This worked very well for me, no derailments after that.

Lee

Posted from BlackBerry

I can do DPU pretty good in HO on a DC layout. I use C44-9W, SD45, ES44AC, C36-7R, SD70ACe and other locos in such service. I will sometimes use DPU on trains with more than 50 cars. Two units up front and one on the rear. Longer trains will sometimes get mid-train DPU/helpers. Doing push/pull locals are fun as well. Like someone posted, it's about body/frame mounted couplers and proper weight of cars and metal wheels, also the proper placement of cars in the train.

SantaFeRuss