Turn out # and track radius

Discussion in 'FAQs' started by nopoop, Jul 1, 2001.

  1. nopoop

    nopoop New Member

    After taking the lady ( my RR partner ) to see the HO Bachmann Shays at the local hobby shop...

    We be doin HO [​IMG]

    Now tentitive plans call for a shortline ( hence the shays ) with an interchange with a medium sized railroad. Maybe a couple of camelbacks or something different looking around that size.

    So I want to keep my radius at "least" 24 and preferably more.

    That interchange just might have passenger cars...who knows [​IMG]

    So what does a #5, #6, or #8 turnout work out to as far as radius goes ????

    Does a #8 curved turnout have the same radius as a #8 straight turnout ????

    Walthers catalog states that there #7 curved turnout has an inside track radius of 24". So taking that at face value, does that mean a #8 straight turnout inside radius would be a little more than 24" ??

    If so, #8's with at least 24" radius curves would be the ticket...

    Not hand laying and the Walthers selection is extensive in code 83.

    Last question I promise........for today [​IMG]

    Tortoise switch machines the way to go ??
    I haven't heard a bad word about them.

  2. Drew1125

    Drew1125 Active Member

    Hi nopoop!
    I've come to the realization that HO is (for me) the best of all worlds. It's big enough to accomodate detailed modeling, & small enough to afford agood ratio of scenery in a modest amount of space.
    I believe that a 24" curve in HO is commonly refered to as a "conventional" curve - not "broad", & not "sharp".
    Using that reasoning, I would think that you would be fine using the #6 turnouts. I've always used Peco turnouts for my HO modeling, & I believe they refer to the "nominal" radius of their small radius turnouts as being 24". For a logging RR though, sharp angled curves & turnouts are very appropriate.
    I plan to model an interchange too, with the C&O, but the section of C&O main is going to be dummy track, with a depot in between the two lines, & a siding for staging cars.
    Hey it's good to meet another handlaying "dropout"! There are some aspects of this hobby that require a lot more patience than I possess.
  3. nopoop

    nopoop New Member

    Thanks Charlie !!

    That's the truth. My problem last layout was 3 months building the room, another 3 months building the basic sub framework, lighting, valances...had the risers and roadbed in...

    and quit....


    Way too much time before I could see one run.

    This time around the rooms being expanded by a carpenter and were going to start somewhere in the middle of this yet to be built shelf style layout. Take a 4 foot section and begin, build a tall trestle, lay the track and finish the scenery off to the "nines" and run that little shay back and forth across it with some disconnects. [​IMG]

    And that ought to get me all fired up [​IMG]

    That and lookin at Shamus's layout [​IMG]

    In that way I can play while I build, instead of just building weekend after weekend.

  4. Woodie

    Woodie Active Member


    The # associated with the turnout is the curve ratio. i.e. # 6 has a 1 in 6 curve ration. # 8, a 1 in 8 ratio. Not to good at triginometry (forgot all that stuff now). Think it works something like a triangle. the turnout forms a right angled triangle for each of the three points. The hypotenuse being the "turned" part of the triangle. SoO if you take the length of the "str8" part of the turnout being say 6" the distance between the "turned" part and the "str8" part will be 1" for a #6. Use of triginometry should tell you the radius then for each curve. Think that's how it works. Any corrections? I'm sure it's written in a book somewhere, much better that I can explain it!

  5. Drew1125

    Drew1125 Active Member

    Hey nopoop!
    All I can say is - been there & done that!
    Also like you, I've come around to adopting a way of planning my RR that's based on a "diorama" style, where I'm going to build the layout in self contained sections, or scenes, & finishing each one before starting the next. each scene will have its own 3 sided backdrop, valance, & lighting. This will restrict viewing angles, & better convey the illusion of distance.
    I've built a small N scale layout mainly as a way to try out these construction techniques, & am very pleased with the results. I'm very fired up now about starting my 1930's era Appalachian short line!
  6. Gary Pfeil

    Gary Pfeil Active Member

    Nopoop, I use 30" minimum radius and still use #6 turnouts, also have a couple #7 curved turnouts, and all my equipment (4-8-4's and passenger cars) negotiate them with no problem. #8's would be best for crossovers, however. I have a crossover w/ #6's, it works, but the lurching is not too attractive.

  7. nopoop

    nopoop New Member

    Thanks all...

    And trig ???


    I concern myself with simple addition and subtraction....

    I've had 2 beers..

    It WAS a sixpac.

    Now if I have a beer and hour and go to bed at nine, when will........

  8. George

    George Member

    Gruss Gott, Nopoop!

    If you're doing a logging line, you shouldn't have any problem in going with #4 switches. The #8 curved switches perhaps close to town, but little engines take tight curves, so you have to have some of them too. I like broad curves, but the small stuff gives you greater flexibility in design than the longer pieces.

    Jeese, I wish Shamus was here! [​IMG] He's the logging expert for sure!

  9. Drew1125

    Drew1125 Active Member

    This is the way turnout #'s were explained to me -
    If you measure out from the frog to a point where the divergeing rails are 1 foot apart, that distance, in feet, is the turnout number. In other words, if the divergeing rails become 12" apart at a distance of 10 feet from the frog, that would be a #10 turnout, & so on.
  10. Woodie

    Woodie Active Member


    Yeah.... same concept. If the rails were 1' apart after 6', then it would be a #6. The number is based on a "ratio" rather than radius. However, does anyone have any figures on the curve radius for each ratio #?

  11. nopoop

    nopoop New Member

    Iddons [​IMG]

    Lol must be all kicking in our hobby backups [​IMG]

    Good to see you [​IMG]

    Indeed a small world...

  12. michael l

    michael l Member


    HO scale #6 switch rail radius = 43"
    HO scale #8 switch rail radius = 67"

    for us O scalers..
    #6 = 83"
    #8 = 132" radius....

    hope this helps.

    michael l.
  13. Iddons

    Iddons New Member

    G'day nopoop !!!
    Small world [​IMG]
    You waiting for WB 3.0 to mature as well ?

    Grant Iddon
  14. nopoop

    nopoop New Member

    Thanks Michael, John Armstrongs book on track planning stated that a #6 will suffice 99% of the time.

    But now I have the *actual* radii [​IMG]

  15. Gary Pfeil

    Gary Pfeil Active Member

    Nopoop, Just remember that crossovers on a double track main fall squarely in that 1%. #6 crossovers will work, well with 4 axle diesels and 40 to 50' cars, and acceptable for larger equipment such as a 4-8-4 hauling a dozen full length paseenger cars. Following correct prototype procedure, you can usually get that passenger train thru the crossover (slow speed xover) If you add diaprahms to your cars, I think you can pretty much forget about #6 xovers. At any rate, #8 will look much better, so if you have the space I recommend #8.


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