Dedicated Helper Units

[tehachapifan]

Off and on for several years, I've pondered the idea of turning some locos into dedicated helper units (I run DC). I've found that using "regular" locos helpers (mid train and especially at the end) will usually result in an eventual derailment, even if the locos are closely speed-matched. I figure this occurs because the helper unit either slows down or speeds up somewhat for whatever reason, as compared to the head end units, or something stutters briefly due to a dirty spot, etc. The train will either stringline or get "pushed" off the tracks.

My concept to perhaps overcome this is to try removing some of the gears in the trucks so that perhaps only one axle per truck (or maybe even per loco) is powered. The ideas is that the one axle will still provide some added power but, should there be a speed variation, the helper loco won't have as much traction to either push too hard or brake too hard. Not sure if anyone has already tried this or if you can even disable some axles and have the truck still run. Thoughts?

[davefoxx]

My gut reaction is that this will not work.  It seems to me that if you reduce the pushing power, you're just going to see more stringlining, because you're still going to have the heavy locomotive(s) in the middle or end of the train.  If they can barely pull themselves, they will not be pushing much.  I expect they'll become anchors.  But, I've not experimented with this, so I could be wrong.

DFF

[wmcbride]

Wasn't there an article on this (removing power fromone truck) that Mike Danneman did in a recent (last year) N Scale Railroading or N Scale Magazine? I know I read it somewhere.

I believe he runs DC and foudn this to be a good solution for his DRGW helpers.

[garethashenden]

There was something in Model Railroader in the past year about the necessity of body mounted couplings with helpers. Essentially, you need to push the cars, not the trucks, otherwise you'll push things off the tracks.

[Csxmtsub]

I run Dc and I took out the worm gear to one truck. I have two helpers each with just one truck powered. The run fine on there own, and push just right. I run long trains and have no problems with 3% grades.

[ryan_wilkerson]

Instead of one truck unpowered, has anyone tried a pair of units: one fully powered and one dummy? If the dummy was trailing, it should provide a drag on the leading helper to reduce it's pushing power. Back when I did NTrack and was going for my longest train, I made sure to put short & heavy cars in front of the helpers. Seemed to work pretty well.

[peteski]

Instead of one truck unpowered, has anyone tried a pair of units: one fully powered and one dummy? If the dummy was trailing, it should provide a drag on the leading helper to reduce it's pushing power. Back when I did NTrack and was going for my longest train, I made sure to put short & heavy cars in front of the helpers. Seemed to work pretty well.

With the current design standards of a majority of model engines, thanks to the pointy axle-end bearings, they roll almost as freely as boxcars.  The only extra drag is created by their weight.

[ryan_wilkerson]

With the current design standards of a majority of model engines, thanks to the pointy axle-end bearings, they roll almost as freely as boxcars.  The only extra drag is created by their weight.

Going with that thought, I wonder how helpful it is then to disable one truck on a locomotive?

[basementcalling]

Wasn't there an article on this (removing power fromone truck) that Mike Danneman did in a recent (last year) N Scale Railroading or N Scale Magazine? I know I read it somewhere.

I believe he runs DC and foudn this to be a good solution for his DRGW helpers.

Yes, it was in this issue. One copy left at MBK.

http://www.modeltrainstuff.com/N-Scale-Railroading-Issue-072-July-August-2012-p/nsr-072.htm

[sp org div]

Russ,
If you dont want to modify your rolling stock, then I am thinking your idea is the next best solution to make it work, especially for six axle locos.  Perhaps trimming off the teeth on one wheelset at a time from each truck, until you find a good balance point with reliable Ops.  For four axle locos, sounds like Mike D's idea would work well.... only other alternative to run powered Helpers I know;
Modify the rolling stock.  I run DCC (assuming that isn't mandatory), with low profile wheels.  I gave up on running helpers all together until I stumbled on Joe Gartman over at the GEHAMS club.  He brought some of his modified rolling stock over to run on my layout, and demonstrated to me just how easy it was to run Helper Ops....
... that is, if you want to take the time to Body Mount couplers on all your rolling stock.  I have not yet completed my whole fleet of rolling stock, but more than enough for all my Westbound Lumber Drags that get Midtrains for the climb up to Summit.  Even with the sloppiest of train handling, very rarely will we encounter a mishap of any kind, but it is still advisable for Helper Crews to make some attempt at matching train speeds with the Head-end Crew.  Glad to see more manuf. producing rolling stock with body mounted couplers now days.

Jeff
http://espeeoregondivision.blogspot.com/

[peteski]

Perhaps trimming off the teeth on one wheelset at a time from each truck, until you find a good balance point with reliable Ops.  For four axle locos, sounds like Mike D's idea would work well.... only other alternative to run powered Helpers I know

There should be no need to permanently modify (trim off) gears on the wheelsets. Usually there are idler gears between axle gears on 6-axle trucks. Simply removing the idler gears will accomplish the same thing

[Glenn Poole]

Off and on for several years, I've pondered the idea of turning some locos into dedicated helper units (I run DC). I've found that using "regular" locos helpers (mid train and especially at the end) will usually result in an eventual derailment, even if the locos are closely speed-matched. I figure this occurs because the helper unit either slows down or speeds up somewhat for whatever reason, as compared to the head end units, or something stutters briefly due to a dirty spot, etc. The train will either stringline or get "pushed" off the tracks.

My concept to perhaps overcome this is to try removing some of the gears in the trucks so that perhaps only one axle per truck (or maybe even per loco) is powered. The ideas is that the one axle will still provide some added power but, should there be a speed variation, the helper loco won't have as much traction to either push too hard or brake too hard. Not sure if anyone has already tried this or if you can even disable some axles and have the truck still run. Thoughts?

I have done this with great success, using DC also.  First, I take engines that are evenly matched.  2nd, I remove enough gears that I have only one or two axles powered on each loco.  This is just enough power to move themselves  .  These gears can always be put back in at anytime.  In one case, where I failed to speed match the engines with the head end power, I had some problems so I just made the entire engine on the  pusher  powerless and now it just rides around like another car.  Two train I have two 6 axle pushers each and never a derailment.  I think the key is that you need front end power to pull the train and your pushers are just there for the looks, not pushing nor pulling.  I pull 40 car trains up a 2 percent grade around 180 degree turn with a radius of 22 inches.  I think all my pushers are behind cars (properly weighted) with truck mounted couplers.

[superchief]

What I have done on the Santa Fe - all the way is I run four F units(older/ heavy revised) on my thru trains, I have removed both worm gears and the motor from the rear two units, now the train CAN NOT pull the hill without help. Then testing helper engines I ended up with a DCC friendly F unit ( much less weight than my older f units) and a second F unit with worms/ motor removed. This is just enough push to get the train over the hill, I have even cranked the helpers up full speed and it will not derail the train!!! Perfect!!!  My biggest problem is guest operators not reading the paperwork to pick up the helper engines! Gordon 

[LV LOU]

I've done this for decades..I do Peteski's idea,just removed the idler gears from the truck.The way I handled it was,remove one gear at a time,then try the loco set until it had just enough power to propel itself,and add just a little to the consist so it actually acts like a helper set.I wouldn't disable one truck,and leave all the gears in the other,or start by removing the gears on the ends of the loco,to keep good electrical contact.If anything,just leave the front/rearmost axle sets,and run with it.Of course,traction tires are not welcome..

[Cajonpassfan]

I think Gordon is on to something...
I'm still not fully operational, but testing helpers on my 175' long 2.2% twisting grade from San Bernardino to Summit, with mostly 40' and some 50' cars and a handful of long gons, and mostly talgo mounted couplers, it seems that the optimum scenario is for the rear end helpers (pushers) to have only enough power to push about a third of the train, and head end to pull not quite the full train. Jeff is right, body mounted couplers work better (and boy, do they work beautifully on Jeff's Cascade layout!) I'm just not there yet...too many other projects. My standard trains are about 25 cars, so the head end should handle no more than 20, and helpers no more than 8 -10. I do run on DCC with a dedicated helper crew. I've also learned that having cars consistently weighed at NMRA standard or better is essential ... This becomes difficult to achieve with some cars, like empty coal gons returning east.... Maybe the slow "Drag" of empties returning east doesn't get a rear helper....
Diesel helper sets are relatively easy to "detune", steam is more challenging, starting with elimination of traction tires....still experimenting with all that. Tbc....
Otto K.
Modeling Cajon Pass circa 1950