trains say run them on radiuses this or bigger

[trainman1248]

so what i would like to know is if you are in a really tight predicament could you go with a smaller radius them what is suggested as long as it not overly crazy?

[ACY]

They tell you the minimum radius for a reason, so to answer your question you should stick to the manufacturer's suggestion or even have slightly wider for more reliability. There are a couple exceptions, for example some HO Rapido passenger cars need 26" radius with all detail parts present, but if you remove most of the detail parts and add long shank couplers they will run on 24" radius.

[ebtbob]

    There is one "general rule of thumb"  from the manufactures.   In the diesel world,  most manufacturers suggest 4 axle diesels for any radius under 22 inch.   For 6 axle engines,  22 or bigger is the suggested radius.
     In the steam world,  from personal experience as well as info shared with me from other modelers,  take the suggested minimum radius and add 2 inches.  So if BLI says one of their steams is good on 22 inch radius,  assume you need 24 inch radius.
     As far as rolling stock goes,  if you try to run long passenger cars on a radius that is too tight,  you may find that the inside corners of two coupled cars will actually meet causing derailments.   Usually though,  it is just that the couplers do not have enough flex to allow two cars or more to negotiate a tight radius.

[jward]

here's another rule of thumb. take the length of a piece of rolling stock, measure the length and multiply by 3 and it should run on that radius. you can often round down to the next smaller size of curve.
example, a 40 foot car is about 5" long, and will run on 15" radius track. a 50 foot car is about 6.5 inches, 19.5" radius isn't made but they will work on 18" radius. most 4 axle diesels are about 50' in length. most 6 axle locomotives are 65' or longer which equals about 8" or longer. they will work on 22" radius or larger (bachmann doesn't make 24" radius).......for most steam locomotives, use the length of the locomotive minus the tender in your calculations.

anything less than this rule, you'll need to experiment. some will work, some won't.

[trainman1248]

ok thank you

[bobwrgt]

Minimum radius is just a suggestion. In most cases i have found you can run most HO engines on less than the minimum suggested. All you need is good track work that is level and true. On 6 axel diesels i use a first car with a long shank coupler to allow for the swing. If you have switches in a curved section or close you might have a problem.
If you have a specific model or engine ask on the forum to see if others are running then on smaller radius. If i went by the minimum listed i would not have purchased half of the engine i run.

Bob

[trainman1248]

ok thank you very much ill keep that in mind