I am slowly (VERRRY slowly) putting together a logging layout and initially believed the stories of Shays and Climaxes handling steep grades and tight curves. A few test track runs sent my HO Climax off to the good folks at the Bachmann repair shop to replace gears. There is no mention in the paperwork that came with my Shay nor Climax stating their minimum curve radius nor maximum grade and I have now redrawn my layout plans to stay with 18" minimum radius curves. I'm still scratching my head about lowering the grade to something less than 4.0. I guess the scale models of these small locos don't live up to their full size big brothers- but that's a guess. Anyone out there know what the safe operational range is for the Spectrum Shay and Climax in regards to grade and radius? I was cautioned by the repair shop that steep grades really do stress the Climax's drive line after the last repair. I really like those little locos and don't want to send them off for more $20 repair jobs. All work has come to a stop until this problem is addressed. Please help reverse the current economic problems and get my track laying crew back to work! TIA, Roy
Roy Onward into the fog http://s1014.photobucket.com/albums/af269/looseclu/
You should be able to do much tighter radii that 18"--maybe as low as 12" but you might want to do a test to see if it is how you want it to look. When I designed my logging I planned for 4%, but I never built it so I can't tell you how it worked.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
I don't own either of these particular locos, but I am familiar with operations of HO geared locos on tight grades and curves. So my comments are somewhat generic.
With respect to grades and drive train stress, my 1st question is whether or not the locomotive(s) have traction tires. If there are traction tires (anything but metal on all the drive wheel treads), all bets are off. You need an ammeter (a special ammeter if on DCC) to ensure motor/drive train are not being over stressed. If you have all metal drive wheels, then driver slip is the safety valve that prevents motor or drive train overload. In an HO geared locomotive of reasonable design, it is nearly impossible to add enough weight to move wheel slip into the dangerous range. A gearbox(es) with excessive friction is about the only way to cause damage.
Since your Shay drives by the lineshafts, which should be more delicate than the hidden drive shafts in the Climax, I would expect the Shay to more likely to have problems from drive train shaft. The Climax drive is pretty similar to diesel models, and should be quite robust. IMHO, if the Climax is over-stressing the drive train on steep grades, there is a design or manufacturing issue. It sounds like the drive train has some binding in it, which is causing your gear problems. Again, these thoughts are out the window if you have traction tires.
I would expect either locomotive to pull itself up an 8% grade without problem. At 6%, perhaps a car or two. At 4%, HO locomotives typically haul about 25% of the cars they can on level track. Adding weight, and keeping the weight evenly split between the drive wheels can increase these numbers. Again, the assumption is no traction tires.
As far as curve radius goes, the telescoping of the line shafts is usually the limiting factor on model Shays. Therefore, the minimum radius will vary, depending on whether the line shafts are on the inside or the outside of the curve. The Shay is a model of a very large Shay, and with 3 trucks, it may well need 18" radius curves. As far as the Climax is concerned, the ability of the trucks to rotate while keeping the drive shafts properly engaged is the limiting factor for curve radius. I would expect the Climax to do 15" radius or sharper curves if the trucks are not striking any part of the body or detail when rotated. In any case, build a test track of your desired curve radius and check the operation, in both directions, and with cars coupled.
Testing for grades becomes important if you are going steep than about 4%. Set up a board with a couple of lengths of flex track for test. Elevate one end to the desired grade, and test. Then you will know.
Hope this helps.
Fred W
Unless you're using cars with body-mounted couplers you'll probably want to stick to at least 15" radius in HO; 18" would be better.
I have a Bachmann Climax. It's a great runner, rolls along steadily at 7-8 MPH but it's very small so doesn't have great pulling power. IIRC when testing it on my last layout it could only pull only 2-3 cars and a caboose up a 2% grade. If you want to go steeper, you might be limited to one or two cars...but that's not unheard of, I've read about grades on logging railroads where the engine could only take one car at a time.
I have the Bachman Climax and a PFM 3 truck Shay. They will both do 4% and 12" EXCEPT - the drive mechanism on both get very fussy after 18" and cannot be counted on. The Climax is better in reverse than forward. My guess is that to get 12 " and 4% you will need to be either very lucky or willing to fine tune your engine in some way.
Keep in mind an 18"R curve IS a very sharp curve!! The sharpest prototype mainline curve used works out to like a 34" curve in HO - and trains would be restricted to 20 MPH on it. Normal mainline curves would work out to 100" or more in HO.