Comments on: Minimum Track Radius

By: Frank B

Frank B — Wed, 20 Nov 2024 14:34:55 +0000

The manufacturer’s item specifications (in the user manual or on their website) should state the minimum track radius the locomotive is suitable for.

By: Ricardo

Ricardo — Thu, 25 Jul 2024 03:25:44 +0000

Hi David, ups which diesels need 30″ minimum radius?

By: David Stokes

David Stokes — Sun, 16 Jun 2024 10:12:53 +0000

How timely
I have two three axle locos that have refused to behave on curves that never bothered thenm before. The radius was 24 iches.
I have been advised by one of my NMRA mentors that such locos need 30″ minimum radius to be happy. He also said that some manufacturers make the central axle on 3 axle bogies very tight. He uses 14mm as his back to back, he eases the axle mounts so that they have easy slide slip so that they follow the rail. Good luck with 18″ – the loco modifications as you say “are not for the faint hearted”.

By: Frank B

Frank B — Thu, 13 Jun 2024 09:41:39 +0000

A trick that is used by some manufacturers on long steam locos, is to remove the flanges on the middle driving wheels. This allows the loco to go around tighter curves.

By: Ken Holbrook

Ken Holbrook — Thu, 13 Jun 2024 03:41:52 +0000

Hey Ronnie, that’s a great question. Most locomotive manufacturers suggest a minimum of an 18” radius for most 4 axle locos. Some 6 axle locomotives do fine on an 18” radius though many do not. I’ve actually had to remove the chassis of a BLI SD-35 6 axle loco to modify the minimum turn radius with my Dremel tool. It’s not for the faint of heart, that’s for sure. But if done correctly you can get a 6- axle loco to navigate a 16” radius with ease! But if you want to stick with out of the box, use 18” as a baseline and you can’t go wrong.

By: Jim Junod

Jim Junod — Thu, 13 Jun 2024 03:26:25 +0000

Two axle units can handle an 18 inch radius but three axle units operate best on a minimun 22 inch radius. The best practice is to use a 22 inch radius or twenty four inch radius.