As mentioned before, I’m now back into the hobby after a 25 year absence. I’ve now mocked up my 4X7 layout using Atlas code 100 track. My curves are primarily 18" with 22" being used when possible. My sidings consist of one straight piece (to mount my uncoupler) with the remainder being curved (due to space limitations). All my freight cars are 40 footers with body mounted kadee (and a few copycat) couplers. Is there any way to get these to couple on curves?? It kind of defeats the purpose of having sidings if I can’t couple the rolling stock!
Tight curves like this are the main reason that earlier manufacturers went with truck mounted couplers. It can be done that Kadees will couple on the sharp curves, but the cars in question almost have to be the same length and the same distance from end to kingpin (truck mounting point). Plus, both cars need to be on the straight or the same radius curve.
Longer cars will have to be done manually. The shorter the rolling stock the better chance you have to couple in turns. I run mostly 22 inch radius and my medium to long cars don’t couple
Here are a couple of empirical conclusions derived by experimenting with Kadee couplers over several decades of time:
Reliable push-together coupling of identical cars (car geometry, not necessarily similar appearance): Minimum curve radius = 3 times car length over coupler faces. (HO, 40 foot cars, 18" radius)
Reliable coupling of similar cars (some 50 footers among the 40s): Minimum curve radius = 4 times the longer car length over coupler faces. (HO, 50 foot cars, 30" radius)
Reliable coupling of anything: Minimum curve radius = 5x longest car length over coupler faces. (HO, full-length passenger cars, auto racks and humonguboxes, 60" radius)
Reliable automatic uncoupling requires either both cars being uncoupled to be on straight track or on a uniform radius half again larger than the coupling radius.
For the radii listed in the OP, anything longer than an ore jimmy might be impossible to uncouple magnetically. In the absence of long-enough tangents, my own preference is to use Ye Olde Shish-Kebab Skewer.
Chuck (Modeling Central Japan in September, 1964 - uncoupling on tangent track only)
Forget the uncoupler magnets. You’re probably going to need skewers to align the couplers for coupling on curves with less than 4-times-car-length radius, so you might as well use a skewer to uncouple. You will be able to moderate the curves since you won’t need straight sections for the uncoupler magnets. Also, you’ll have additional length to couple cars since you won’t need to futilely attempt coupling over an uncoupling magnet.
I’m glad to hear that you’ve only “mocked up” your track, because you will not be able to couple/uncouple on the curves you’ve got.
Instead, give your track plan some thought. If you’re hitting a brick wall on this, see if you can post a picture. It doesn’t have to be fancy - draw it on paper with a dark marker and scan it in if necessary - that will work. Some forum members really like collaborative layout design, and will be happy to give you a hand.
Thanks guys. Here is my layout design using Atlas’ RTS software (don’t laugh):
Pretty basic. The reason for this design is I am going to be using DCC and wanted two loops for two train operation. The inner loop will be for switching operations. Since it sounds like coupling on these curves will be impossible, perhaps I’ll remove those three sidings and instead put a small yard at the front (bottom of the image) of the layout using straight runs only.
Oh, here is the layout in the mock up stage. I built the table myself. The legs bolt on for easy moving. Casters make it easy to roll the layout away from the wall to work on it. Nothing fancy but I’m happy with it. The surface is 2" foam.
You may have to decide what you want the layout to do. As it is now you’ve squeezed two separate loops of track into a small space so you can run two trains at the same time, but at the expense of sidings and operation. I’d suggest trimming it down to one loop / oval of track. If nothing else, that will get you away from having track right on the edge of the benchwork. You can bend the oval shape in a little in the middle so it’s kind of a peanut shape to make it a little less ‘trains round the Xmas tree’.
Then you should have more room for industrial spurs. Try to make the spurs so they are straight if possible. If you have to have a curve, have the curve at the end by the bumper rather than by the switch. (So like the spur on the left of your design that is curve - curve - straight - straight, make that straight - straight - curve - curve.) That way you could put a cut of 2-3 cars in the spur, even if most of the cars are on a curve, as long as the car closest to the turnout is on the straight section you should be able to couple with ease.
