What do number 2 and number 3 OO radii translate to?

Discussion in 'HO Scale' started by YoHo, Apr 3, 2012.

  1. YoHo

    YoHo TrainBoard Member

    Anyone know the conversion for Number 2 and #3 radius OO to inches radius? I think they are close to 18" and 22", but I'm not sure.
  2. paulus

    paulus TrainBoard Member

    Hi Yoho,
    OO-scale (1:76) is used by British model railroaders. British trains are smaller then their continental counterparts so by using a different scale their models have about the same size. Both run on HO track, so the track is a bit to wide to prototype standards for OO-models.

    Track radii are not labeled like turnouts, a #2 radius might be used by a manufacturer for a certain radius. Since you were talking about OO-scale I checked the Peco side; could not find anything. All I know is it has been done by Roco. This is a continental firm however and they think HO. As far as i remember the radii used by Roco started well under 18" and with a spacing of about 2,5" it went up.
    Google Roco and you'll find:
    R2 = 14,1
    R3 = 16,5
    R4 = 18.9
    R5 = 21,5
    R6 = 24, and further up.
  3. shortliner

    shortliner TrainBoard Member

    For PECO you need to look for their setrack range (Hornby is complimentary) They are the equivalent to the trainset boxed ranges.
    #1 is 371mm radius, #2 is 438mm, #3 is 505mm, and #4 is 572mm. There is also a "special" curve 32/circle of 859,6mm (designed to use to bring the tracks diverging at a wye point back into parallel spurs. Straights are 41mm,79mm,168mm, 335mm. It is all Code 100 only. Turnouts for the range start at #2 radius - there is no#1. Multiply mm by 0.039 to get the inch equivalent. Note that Roco also did a #0 in brass, a good while ago that was 305 mm - almost exactly 12". there is also said to be an even smaller one by Roco that was roughly 10" radius - but I have never seen one
    Hope it helps you
  4. YoHo

    YoHo TrainBoard Member

    I know that OO is a different scale. I was just looking at various curved turnouts for use in my Yule Central idea and most are quite broad radii. The OO options were the only tight ones. Of course, picking up Peco OO scale equipment may not be worth the costs given what my plans are, but it's worth looking into I think.
    So the Peco curved turnout with a #2 inside leg and a #3 outside leg is going to have a ~17.5" inside leg and a ~19.5" outside leg. Perhaps a bit tighter than I'd like. a #3/#4 curved turnout would be better for my application. I shall see if such exists.
    I assume Peco OO track has the same spring action to hold the points against the rail.

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