Hi, All
Assuming the minimum radius that a car will traverse is limited only by truck swing, can the car successfully negotiate a very short sub-standard curve? By “very short,” I mean shorter than the fixed wheelbase, so that only one truck is on the curve at any time.
I think it’s only a geometry question. It may, however, have applicability to using tight-radius turnouts in an otherwise generous-radius layout.
I’m hoping to learn from the group wisdom on this. 
Thanks,
Steve
Steve,
I think that depends on whether or not anything is coupled to the truck 
A single unit might traverse a tight curve with enough truck swing. Multiple units lashed together might have a different result.
Ralph
How small are you talking? My 1:24 4-wheel stuff with truck mounted couplers will do R1 (4 Ft Dia), even S curves with little trouble. 1:29 Locomotives will not push -or - pull a car through the same R1 turn-outs without derailing the car. Much of my indoor storage yards are R1 turnouts. When switching them with 1:29 locos I’ll use a string of “reach cars” to get through the turnout.
Forget body mounts with tight curves. My body mounted FN3 stuff barely gets through an Aristo “Wide” turnout (approximately 10 Ft Dia).
Edit to add that most of my 1:29 locos will get through a single R1 turnout or around an R1 curve by themselves. When I had lots of R1 curves indoors I used hook & loop couplers on the locos to get around the curves pulling cars.
Hook and loop is what I am using on my logging Rail.
I guess I’m using hook n loop more because of the period than anything.
I blindly fell into a good tracking train because of the look I wanted, and not from any knowledge.
Thanks, guys…that’s all helpful stuff, and I thank you for it.
But the question I’m trying to answer is a little bit different. Here it is again, more specifically, and using numbers typical of LGB 8-wheel freight cars:
“Consider one single car, all by itself, without any couplers at all. The trucks can swivel 25 degrees either side of straight ahead. The distance between truck kingpins is 10 inches. It’s easy to show that the sharpest long curve the car will traverse has a 11.8 inch radius. By “long,” I mean the curve is longer than one car length, so both trucks are on the curve.
“My question is: what is the minimum radius if the curve is shorter than one car length, so that only one truck at a time encounters the curve? Can the short curve be sharper in this case? If so, how much sharper?”
I admit to being a bit odd, but this is the sort of thing I think about when I’m unable to sleep at night but too lazy to get up and do something useful. So if you guys would rather run trains than tackle this, I’ll understand completely.
Thanks,
Steve
May I recommend a glass of warm milk before bed? And if that doesn’t work, two fingers of Maker’s Mark, neat?
Best idea yet, Steve.
I can’t offer much in the way of modelling, however, to use a real-world example, there is a curve in an intermodal yard I worked in. That curve, which really was more of a kink, was so short, it was barely twice the length of of the trucks under a GE DASH-9, yet it made a turn of approximately 30`.
My suggestion would be to take some old track and bend a curve to what you are looking to use, and try it out.