Need to know what the smallest radius is for the Walther’s,Athearn 86 foot Trailer train, boxcars, and auto racks out there. Tried to find info on Walther’s site, no deal. Need this for new track that is to go in for new RR expansion. Now have 22 inches it it doesn’t work well if at all. Send info to OurBaja@yahoo.com.
For freight cars that long, I wouldn’t consider anything under a 28" radius–not only for the overhang, but the space the body length would take on the inside of the curve. especially on passing tracks and tunnels. Actually, cars like that–and scale length passenger cars for that matter–are far more trouble free on 30" radius or above. I can’t speak for long freight cars–the era I model has 50’ maximum cars–but even on a 34" radius–my minimum–scale length 80 and 85’ passenger cars are JUST at the point where they look somewhat prototypical.
Just my opinion, you understand. Other modelers may have different ideas.
WALTHERS heavy weight cars are marked 24" radius on the box. This is the minimum for operation and is not troulbe free. For looks and operation anything 28" or greater is best as stated above. Running Walthers on 24" curves may require trimming the flange on the center sill so the wheelsets do not touch the frame.
On the long cars you may get away with 24" radius. On the locos, speaking for Athearn’s, mine all take 18" radius, including a rtr AC4400, though I did have to modify the coupler pockets so the couplers could swivel.