Track codes

Discussion in 'HO Scale Model Trains' started by AndyWS, Nov 30, 2006.

  1. AndyWS

    AndyWS Member

    Fairly elementary question, but I don't know it because we've only ever used one track code and I don't remember what it was when we first purchased it. What's the difference between the different track "codes", 70, 83, 100 etc? I know it's in the size of the rail but which way do they go, from smallest to largest? Which is the most accurate for prototypical mainline rail, lightweight siding and branchline rail, etc?
  2. fsm1000

    fsm1000 Member

    code 70 is 70 one thousands of an inch.
    code 100 is 100 onethousands of an inch
    the smaller the number the smaller the rails.
    Hope that helps:)
  3. MasonJar

    MasonJar It's not rocket surgery

    Code100 is the scale equivalent of the heaviest rail in use on mainlines today - 155 lb rail. Anything lighter is for less travelled and/or older lines. Smallest stuff would be in sidings that don't see much use.

    I am modelling 1920s and 1930s branchlines, and using Code83 flex. It really is too big for this application - I should use something quite a bit smaller, but that would mean handlaying, and I don't really want to do that. I'll paint the web (vertical part) of the rail dark, which creates the illusion of smaller rail.

    Hope that helps.

  4. jeffrey-wimberl

    jeffrey-wimberl Active Member

    Code 100 is the largest. As the number gets smaller, the rail gets smaller.
  5. 60103

    60103 Pooh Bah

    Scales other than HO use larger or smaller codes than these. Some of them are less accurate models of the rail section (if any are even accurate) because a small rail section is different proportions than a large rail section.
  6. Russ Bellinis

    Russ Bellinis Active Member

    Just in case it isn't completely obvious, the rail is measured in height, so code 100 is 100thousandths on an inch from the base to the top of the rail.
  7. nkp174

    nkp174 Active Member

    Code 100 is correct for 155lb rail...the stuff was pretty much only used on the Pennsy. The Atlas stuff is the old, standard track of model railroaders...and it has not-to-scale ties as well.

    Code 83 is correct for 132lb rail...this stuff is good for modern mainlines and some 1950s railroads. Atlas's Code 83 has replaced their Code 100 as the standard.

    Code 70 is about right for 115lb rail...this is the most appropriate for most transitional era model railroads.

    Code 55 is appropriate for 75lb rail. Good for 1900 railroads, sidings, and heavy narrow gauge. I'd guess micro engineering sells it.

    Code 40 is appropriate for 40lbs rail. It is good for 1880s narrow guage, sidings and logging. You'd pretty much have to hand lay it with glue (on scale ties) since spikes don't work well with Code 40 rail (or so I've heard/read)

    As a rule of looks good if you use one size smaller rail for your branches, sidings, and yards than you use for your mainline. If you want...small industrial tracks on even lighter rail look great.
  8. Jim Krause

    Jim Krause Active Member

    Don't forget that some older rolling stock and toy train sets have off scale wheels that won't work on the smaller size rails. Wheel flanges are too large and hit the ties.
  9. nkp174

    nkp174 Active Member

    This can be a problem! My old Rivarossi (AHM) hudson doesn't like code 83!

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