Modeling Helper Service With A Pusher..

[caldreamer]

On my friend Tom Stack's DCC railroad we would run pushers up the 4% grade with a seperate helper enginner.  It was very tricky to keep in sink with the head end to avoid buckeling the train.  The same law's of physics apply in N scale as they do on the real railraods, so when you do it on a model railroad you get the exact same feel as you would on Donner Pass or Horseshoe Curve.

[markpierce]

....  As long as the pusher isn't pushing the road loco and/or the road loco isn't pulling the pusher, there shouldn't be any problems.

Chuck (modeling Central Japan in September, 1964)

Theoretically, and assuming all your cars like to be pushed uphill on your track.  Chuck, I think I know you well enough to assume you don't have coupler-mounted trucks, least on your freight cars. 

Problems occur when one locomotive stops or starts unexpectedly and abruptly on a curve.  These circumstances can't always be prevented.  Go slow to minimize the potential disaster.

Mark 

[tomikawaTT]

The photo on the bottom of the last page of Norfolk & Western Railway's Magnificent Mallets (subtitled The Y class 2-8-8-2s) is of a Y-6a, number 2160, waiting on a helper siding for the next train needing a pusher.  N&W steel frame cabooses could absorb the 158,000 pounds of drawbar push that a Y-6 could generate at 10mph.

On my model railroad, if the road engine can't take its train up the 2.5% grade from Haruyama to Tomikawa unassisted, it will be assigned a pusher - a locomotive that can't push the entire train unassisted.  As long as the pusher isn't pushing the road loco and/or the road loco isn't pulling the pusher, there shouldn't be any problems.

Chuck (modeling Central Japan in September, 1964)

[dehusman]

The WM would run trains with an engine on the point, 2 in the middle and 3 on the rear.  These were large 2-8-0's (as powerful as a USRA Mikado). 

The Reading ran helpers on the Catawissa branch that ran all the way across the line (100 miles) because there were several hills in succession.  They would gather up groups of up to 9 or 10 engines to return as one move (once again all large 2-8-0's).

Dave H. 

[markpierce]

It was usually most convenient to have the helper at the front end.  Adding/removing locomotives and locomotive coordination is easier.  It avoids the slack action (bouncing around) in the middle of the train (point of changing equilibrium) when a pusher is used.  For that reason, you wouldn't see a pusher on a passenger train.  Pushers were normally used when the combined tractive effort exceeded the strength of couplers and to avoid turning over a long, heavy train on sharper curves.

While inconvenient, pushers were usually placed in front of the caboose for safety reasons.  There were exceptions.  For instance, on the SP a cabforward articulated would always be ahead of the caboose while a small locomotive like a Consolidation could be seen behind the caboose.  In fact, on the short eastbound grade to the Suisun Bay Bridge (between Martinez and Benicia), the Consolidation helper might have a modified front-end coupler so it could separate without stopping the train.

Pushers can be midst the train, not only on the back.  Some railroads added pushers both midst the train and at the rear. 

Using helpers on a model railroader is an exciting challenge, not just to keep the train on the track, but also the switching opportunities for adding and subtracting locomotives, and watering any steam helpers on the way up the grade.  I wouldn't want to attempt this without DCC and a skilled operator for every locomotive.

Mark 

[Mark R.]

A friend of mine used to run pushers on the D&H on Belden Hill. If I recall correctly, the pusher engines ARE attached to the trains brake-line, although the pushers do NO braking themselves. The pusher crew can monitor the brake-line pressure to determine when the brakes have been released and the head-end is ready to pull. It is also required in case the head end goes into emergency - other-wise the pushers keep pushing and could cause the train to buckle.

 The D&H, PRR, RDG,LV, CNJ, and others had modified cabooses that were assigned to pusher districts to make it easier to cut off on the fly. What is done is as the train crests the hill, the pusher engineer will throttle back and in turn the head end will take up the slack created by the pusher, ever so gently, in the mean time the caboose crew has CLOSED the angle **** on the caboose ONLY, not on the pusher engine, the caboose or pusher crew will pull the bin and hold it, as the slack it taken up by the headend, the cut is made and away goes the train and the pusher goes into EMERGENCY and stops, each go there merry way.

The other thing if you have a GOOD pusher engineer and he knows the railroad (meaning up's and down's) he can make a easy day for the headend engineer as he can control the train speed via how much power he is applying. A really good pusher engineer can even help with breaking going down hill, via the DYNAMIC brake, but he really needs to know what he is ding or you could end up with a real big mess!!

We've replicated the pusher scenario quite successfully on my DCC layout using one engineer on the head end and another on the rear pushing .... it went surprising well !!!

Mark. 

 

[danmerkel]

Going way out there on the speculative side of things.

Could you not on a DCC layout, create a consist using the helper and the main locomotive, and synchronize them by running them unattached and adjusting speeds?

Taking that a step further, couldn't you then form a different consist for each locomotive that uses the grade using the same helper so that every train was synchronized?

 But think about this... as the head engine hit the grade, it would slow down as the load of the cars going uphill increased.  The engine at the rear, wouldn't.  Conversely, when the head engine topped the hill, it would start to speed up as its load lightened; the rear engine wouldn't.  So it would take coordination beyond just running two engines at the exact same speed.

dlm

[MidlandPacific]

One other thought: the decision to add power at the rear, rather than the front, of the train can be dictated by some combination of the following:

1) Weight restrictions: bridges may not be able to handle the weight of two or more locomotives. The RGS cut helpers in at the middle of trains after buying the K-27s, because the line's trestles couldn't handle two at once.
2) Smoke: per my previous post.
3) Excessive power: when the 2-8-8-2 was introduced, they could exert more tractive effort than a lot of carbodies or draft gear could withstand. I read a piece by an old SP engineer a few years ago in a now-defunct Pentrex magazine that described the phenomenon of a gondola being twisted out of shape by the sudden application of too much power at the head end.
4) Operations: O Winston Link's books on the N&W have some wonderful pictures of a coal drag cutting a pusher off at the top of a grade without stopping: the engine probably wasn't cut into the train airbrake line, and the rear brakeman simply pulls the pin on the caboose knuckle, and the helper engineer closes the throttle. Saves time and effort.

[jacon12]

Here in central Georgia, where the land is fairly flat I don't think I've ever seen a helper pusher. Many double and triple headers of course. I would imagine that as you get more up into the Appalachian Mountains it may be common.
Thanks for the information.
Jarrell

[West Coast S]

My solution was to standardize all my gear ratios and use DCC. My protoype had grades of 3% and being light branch rail with light bridges, only small steam power was used, hence all cement shipments to name one example were double or triple headed in 10-20 car trains with power on either end, cut in mid train or a combination of all three.

[jacon12]

Thanks to everyone for the information. I'm that more educated.

Jarrell

[Anonymous]

QUOTE: My question is, where are these helpers (prototype) kept and what does the crew do when they are not helping? I mean is there a side track they stay on and they just wait there or how does it work?

Yes, In Altoona helpers wait in the yard or next to Alto tower for the next assignment. They help the train over Horseshoe Curve through Galitzen into Cresson where the helpers are let off. A small service facility is located there. There is enough traffic here that they dont sit very long!

[SpaceMouse]

Going way out there on the speculative side of things.

Could you not on a DCC layout, create a consist using the helper and the main locomotive, and synchronize them by running them unattached and adjusting speeds?

Taking that a step further, couldn't you then form a different consist for each locomotive that uses the grade using the same helper so that every train was synchronized?

[MidlandPacific]

Two potential problems: either jackknifing a train as the helper's speed exceeds that of the leading locomotive, or pulling out a coupler if it falls behind. MR ran an article in the 1960s that explained the ins and outs of voltage measurement and speed curves; if you can find it, it may help you.

If you're really looking for a challenge, try this: the old Midland Terminal used to accumulate ore cars at Colorado City. When they had thirty or forty of them, they would assemble a train for the run up Ute Creek Pass to the yard at Bull Hill, near Cripple Creek. Because the ascent of Ute Creek Pass was a stiff four percent, and because the MT's roster was composed largely of ancient consolidations, they would simply put three or four of them on the train and make the trip up as a unit. There were several close-clearance tunnels on the pass, though, and to avoid asphyxiation, they spaced the engines ten cars apart through the train.

THAT would be an impressive site in HO scale!

[twhite]

Jacon--in the steam era, the helper locomotive was usually assigned to the specific Helper District and had a home base that it returned to after every job. For instance, on SP's Donner Pass line, the westbound helpers were stationed at Truckee, CA at the base of Donner Pass. They'd pu***he train 18 miles up the pass to the summit at Norden, where they were turned (the turntable was in the middle of a snowshed) and returned to Truckee for the next job. In Truckee, there was a 'baloon' track for turning the locomotives (sort of like a hidden reverse loop on a model railroad). On the west side of the pass, the helpers were stationed at Roseville, in the Sacramento Valley, and after their service (80 miles over the Sierra) they were also turned at Norden and then sent back to Roseville. Often, additional helpers were cut into the train at Colfax, midway up the grade, these would often be cut out at Emigrant Gap, where the 2.2% grade eased on another 'baloon' track. Other railroads had similar facilities for turning helper locomotives (a 'wye' track, for instance). Often, if the traffic was heavy, helper locomotives would be held at certain stations and then run back to their various starting points in 'trains'. On Tehachapi Pass, for instance, both SP and Santa Fe would hold their helpers on the summit, and then run them back to their base in 'trains' of anywhere from four to twenty locomotives.
One of the tricky aspects of modeling 'pusher' service on a model railroad is making sure that the helper locomotive is in sync with the main loco, otherwise you might end up 'accordioning' your train--pushing it so tight it derails. On the prototype, during the early steam era, the speed of the pusher was regulated by whistle blasts between the locos, later phones and radio communication between the two cabs was established. In model railroading there are a lot of variables--weight of the cars, 'synching' the locomotives--and even then it's a tricky prospect. Much as I like using pushers on my own model railroad, I usually end up double-heading. But nothing looks quite as fascinating in a helper district as a locomotive tacked on just ahead of the caboose, working it's way up a hill.
Tom [:p][:p]

[jacon12]

In John Armstrong's great book "Track Planning For Realistic Operations", he talks about railroads that have to have helper locomotives for trains climbing steep grades. In this section he goes into why the company uses pushers instead of another puller etc.
My question is, where are these helpers (prototype) kept and what does the crew do when they are not helping? I mean is there a side track they stay on and they just wait there or how does it work?
Do modelers usually try to include this feature on their layouts?
Jarrell