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I'm getting started on my first layout and trying to figure out which of my locos will work on 18" curves. I've got mostly older Athearn diesels (GP35s, GP38-2s, GP40-2s, SD40s, SD40Ts,SD45s). Will my 6 axle locos work? If they do work, how will they look? Also, what is the difference between Atlas code 83 and code 100? Any recommendations?
I run 12 wheeled locos on an 18 w/o incident. The diffrence in code 100 and 83 beside 83 having brown ties and 100 having black ties is the height of the rail. Code 83 is more prototypical. If you are running really old rolling stock and locos you may want to go with code 100 because some older models will have deeper flanges (little lip on the wheels)
With curves bigger is always better. 6 axle locos might go around an 18"rad but not all cars will stay coupled to them. They will look very uncomfortable as well. FYI a 18"rad works out to a 45 degree curve (real railroads measure curves in the amount of curvature per 100 linear feet, this curve turns 45 degrees in 100 feet) On real railroads 10 degree curves can cause stringlining and other problems.
Code 100 is 0.100" tall, code 83 is .083" tall, code 55 is .055" tall and I am sure you can figure out any others you may come across.
Using six axle locomotives on 18" curves can be done. The track has to be perfect though. I have a passing siding with 18" curves and I can run six axle diesels through the siding but at no more than about 20 scale mph before problems set in. If you have any cars with couplers the aren't at the right height or don't swing feely, you'll find out about them on an 18" curve. I can even run 80's passenger cars through the siding but the overhang is so bad that they really look ridiculous. I'm will to accept these issues with a passing siding because 18" was the biggest radius that would fit. Having mainline track with 18" radius curves and six axle trucks is going to make you real nervous a lot of the time. If there's any way you can find the space, I'd urge you to use at least 22" radius curves on your mainline.
All my curves are 18" radius. I run a lot of four axle locos and also quite a few six axles locos. Alco PA's, EMD E6's, E7's, SD40-2's, something that looks like an RSC-3. I also occasionally run a Mehano 2-10-2 with no problem.
My experience says you are going to have some trouble with 6 axle units on 18" radius curves. Is your space so limited you can't go to even 20"? If you have to stay at 18" then certainly look into building easements into those curves.
Easements aren't absolutely necessary. As I indicated earlier, all my curves, because of space constraints, are 18" radius, Bachmann nickel silver EZ-Track at that. I have no easements. The only six axle unit I had any trouble with is an Athearn AC4400. No trouble with it staying on the track. It would run on 18" all day long if I let it. The problem was the couplers. They swung out so far that the car immediately behind the loco would be pulled off the track. I performed a little surgery on the loco and changed the coupler mounting so that the couplers can swing. This necessitated opening the pilot some so the coupler could move from side to side.
Hey Jeff: I am pleased that you found a solution that works for you. That is what is most important. You have probably also figured out that placing a short car immediately behind the engine during your operating sessions will assure you smooth sailing.
My experience says you are going to have some trouble with 6 axle units on 18" radius curves. Is your space so limited you can't go to even 20"? If you have to stay at 18" then certainly look into building easements into those curves.
As I've said before, you can run six axle locomotives on 18" radius curves as long as the trackwork is perfect. My experience is that it's not the locomotive that's the problem, it's the train. As has already been talked about, you can have engines with insufficent coupler swing for 18" curves and it will pull the following cars off the tracks. Jeffrey and Oldrobert have both found workarounds to that problem but it will be a continuing issue. In general, I'd sacrifice almost anything on a layout to get at least 22" curves.
I can even run 80's passenger cars through the siding but the overhang is so bad that they really look ridiculous. I'm will to accept these issues with a passing siding because 18" was the biggest radius that would fit. Having mainline track with 18" radius curves and six axle trucks is going to make you real nervous a lot of the time. If there's any way you can find the space, I'd urge you to use at least 22" radius curves on your mainline.
