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Minimum HO Turn Radius

Frank writes:

“I’m a novice HO model railroader. I usually set up a simple oval under the Christmas tree annually. I’m bored with that. Furniture confines me to 5′ x 7′ area. I want to add a couple turnouts, a 2nd oval, and sidings for some wild west buildings. What is the minimum HO turn radius for 4-4-0 and a 4-6-0 1870-80’s steam locos and that era freight cars?”

5 Responses to Minimum HO Turn Radius

  • Nigel says:

    Being British, I can only speak for 00 scale although it uses the same track as H0.

    The general recommendation seems to be a minimum radius of 438mm (sometimes referred to as second radius by the likes of Peco & Hornby). Your 4-4-0 may cope with less but the 4-6-0 may struggle with less, particularly if all of the driving wheels have flanges.

  • Joseph Tillman says:

    For HO scale, the 4-4-0 and 4-6-0 will handle 18″ radii curves with ease. You mentioned the locos were from the 1980s so they might well be old Tyco or AHM models. Those could usually do a minimum of 16″ radii curves pretty well and possibly 15″ if you are not running at too high of speed.

    For locos of that era, stick with Code 100 track as the flanges might hit the heads of the plastic spikes molded onto the ties of Code 83 or smaller track.

  • Frank B says:

    Test the loco of a sufficient length of the curved track you intend to use. 
      If it works, make a note of which of your locos works on which minimum radius. 
     Then buy more of the track that works. Keep the track that doesn’t for shunting yards, or lines with smaller locos. (Or just for testing.)
     Manufacturer’s websites should state the mininum radius each loco is suitable for.  
     If they don’t, hit the “Contact Us” button and ask them.

  • frank feagan says:

    Thank you. As I said, my trains are of the 1870 steam era (old cowboy west). Most of my track is Bachman (Not the snap track) and probably some other brands from random eBay purchases. Since they are a mixture, I guess I’ll make some circles with each type of track and measure the radius of each. I’ll experiment with the various track radii and see what I can figure out.

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