Tight HO radius question


Marlin39

Well-Known Member
Let's say I am building an HO shortline that uses a 70 ton and 45 ton switchers. All cars are 40' or less. I will have 12'-14' in length, but probably a maximum of only 36" in width, on the ends. Will I be able to get away with 15" radius on the ends for continuous run?
 
My advice, and it's often shared widely by many who answer this question on forums scattered across the internet: Mock it up on a piece of plywood, fasten the track curves temporarily with track nails, make sure you add any super-elevation or easements, and then run your rolling stock...COUPLED... trailing and shoving. This way, you'll have pure, empirical, evidence that what you want to do is reasonable and achievable.

Mock it up and do trials. It'll take an hour at most. The knowledge will last you your lifetime.
 
I certainly echo Crandell's advice, but I am pretty certain that with what you're planning to run, it will work. Try this though, start each end of the half circle with an 18" radius curve and fill the middle with 4-15" radius curves.
 
You will not be able to couple cars on the curve.

This will not be an issue nor ever attempted. I knew this would be an act of futility if I tried.;)

"Try this though, start each end of the half circle with an 18" radius curve and fill the middle with 4-15" radius curves. "
This is an outstanding idea! Much appreciated!
 
Most of the how tight a radius questions really boil down to how good is your track and equipment? If the track has kinks in it, uneven gauge, line and surface, then you will have problems. If the couplers are mismatched or the trucks stiff, the cars unevenly weighted or the wheels and axles inconsistent, then you will have problems. The closer you get to absolute minimum, the more exceptions to other standards become a problem.
 
I remember back in the day, my dad would shim under the outside rail to give it a slight bank on tight corners. It doesn't take much to make a huge difference.
 
"Try this though, start each end of the half circle with an 18" radius curve and fill the middle with 4-15" radius curves. "
I did that once to fit a layout into the top of a bunk bed space. It worked even better than one would have guessed.
 



Back
Top