I’m in the final stages of designing my model RR.I’m trying to decide the grade for a short line coal and lumber R.R. On a straight track,no curves, my Climax will push six cars up a 4% grade.I’m hoping it will push five cars on a 3% on an 18 inch radius.It did the six cars very well.My question is,for both the shay and climax ,when they are coming downgrade they are jerky in their movement.Is this harmful to the locomotives?
Terry
I have several Bachmann Spectrum HO scale 3-truck Shays and none of them exhibit this problem – but I don’t run them on that steep a grade, either. The herky-jerky motion is most likely due to the amount of free play in the mechanism. Too much load could conceivably cause undue wear or even breakage.
One possible way to stop this is to have rolling stock that doesn’t roll well and puts a drag on the engine when going downhill.
And up hill too [:O] [:D]
I have 2 of the shay’s and one runs like a dream, the other was trouble right out of the box. It had no slow speed, and a very bad jerk even running on flat track. I opened the gearbox on it loaded it with plastic compatable grease (it seemed a little dry by the way), reasembled it, and foud that I also had to loosen the gearbox cover screws about a 1/4 turn to keep it from binding the gears. It now runs quieter, and slower the the “good” one.
Hope this helps. Robert
Thanks all,very good advice
Check my recent post on grade effects in Layout & Layout Building "Grade Effects on Hauling Capacity "
I would calculate you’ll only get 4-4.5 cars up a 3% grade with 18" radius curves. The effective grade is about 4.8%.
I’ve heard that the Bachman Shays usually “jerk” going downhill and that this is normal. You might check out the Bachman site as they have a forum “BachMan” or something like that. My Shays have some “jerk” going downhill but it has never been a problem. I don’t know about the Climax.
Marty
I have two Bachmann Shays. Both run beautifully. Smooth, no jerk up or downgrade. I use them on a 5% grade up to my logging camp with <18" curves on the grade. That’s actual 5%, not effective with the curves. One is set up as an oil burner and will pull 9 standard NMRA weight hoppers or ore cars up, no problem. The other is set up as a wood burner and will pull 7 (the wood burner is lighter because the “oil bunker” is a hunk of solid metal that adds quite a bit of weight). I imagine they’d do more than that with my log cars (I have Rivarossi log cars that are <NMRA weight…) though I don’t actually own more than 8 of those to try it.
On the other hand, my Mantua 2-6-6-2 logger (which also has traction tires in addition to 12 driving wheels) will pull pretty much anything I’ve ever hooked to it up that grade. I’ve put 8 hoppers, 8 ore cars and my 6 log cars all on it at once with no problem. I’d probably run into problems stringlining cars around the curves before I ran out of pulling power with that one.
As to trying to “calculate” it objectively or mathematically, I don’t think that’s effective. I have never found the various “effect of grade on pulling power” and/or “calculation for effective grade with curves” charts or calculators to work worth a hoot in the real world. In fact, I’ve used an awful lot of foul language every time I designed a grade using those articles, formulas and charts – only to have to rework it when the real world laughed at “theory.” In the end there are too many variables with car weight, rolling characteristics, size of truck and wheels, metal vs. plastic wheels and how freely the trucks swivel and camber all affecting the issue (and doubtless others I’ve not thought of).
Example: I have one single ore car with a “draggy” wheelset. Can’t for the life of me figure out why and haven’t got 'round to replacing it yet. The point is, if I put that car on the Shay and try to pull it up, I’ll reduce my pulling ability from 9 cars to 3! How do you calculate f
I have both locos that I run on my Sawyer Lumber branch. They both run real well and I haven’t noticed any problems…But then again, my ruling grade is in the helix, at 2%, maxing at 3% at the very top. I also have a 30" radius in the helix and that too, will have an effect (tighter, being harder to pull…Maybe going down hill to). None the less, even coming through an “S” curve at the top (just after the 3%, mellowing to less then 2%) I can’t say I’ve seen “jerking”, but I’m going to “load” those SL locos and give a watch!!
This is inherent in most all gear drivetrains. Even the prototypes exhibited this behavior somewhat. There are some people who try to modify the drive train and remove the “slack”. Usually doing this will eliminate most of the problem, but at the expense of good, smooth low speed opertaion. I’d just leave it alone.