track gauging

Discussion in 'FAQs' started by Nomad, May 23, 2007.

  1. Nomad

    Nomad Active Member

    Hi everone:wave:
    Everybody complains about there trains clanking and banging and derailing through the turnouts. I found this websight that explains why. What he says explains a lot to me. See what you think. The only problem is how to fix the rtr turnouts.

  2. pgandw

    pgandw Active Member

    This is one of my areas of particualr interests. Unfortunately, narrowing the gauge on most commercial turnouts requires major surgery. It's probably easier to yank out the worst offenders and hand lay new ones in their place. A few things one can do with commercial turnouts:

    - Check the guard rails carefully. Often they are set too close to the frog (Atlas often has this problem). This lets wheels "pick" the frog. Put a strip of thin styrene on the side of the guardrail close to the stock rail.

    - Make sure the tops of rails are level all the way across the stock rails, guard rails, wing rails, and frogs. Any dips or bumps need to be fixed. Sometimes, frogs are higher than the surrounding rails (Atlas again is a common culprit). Applying a soldering iron to the metal frog and pushing it down slightly as the plastic base softens sometimes works.

    - sharpen the end of the points and chamfer the end where it sits against the stock rail. This helps prevent "picking the points".

    A caution to narrowing the gauge - the narrower the gauge (which also narrow the flangeways at the frog), the bigger the minimum radius required by the rolling stock.

    Although I don't believe the NMRA did this by design, the slop caused by the difference between the wheel gauge and track gauge does allow our models to squeeze through much tighter turns than they could otherwise. If you narrow the track gauge to NMRA minimum (there are expert advocates for even narrower), the LDSIG rule of thumb becomes the practical minimum radius standard. Longer truck wheel bases will bind going through curved narrow flangeways and/or sharp curves when track is gauged at or less than minimum.

    The LDSIG rule of thumb states that minimum radius is 3 times the length of the car over the couplers for good operation with body-mounted couplers (appearance not considered). In HO, this means the 18" radius is only good for 40ft or smaller cars and locomotives. The 22" radius will pass perhaps 55ft cars and locomotives. Full size passenger cars with 6 wheel trucks should have at least 36" radius curves.

    P87 runs into the same minimum radius issues. When you take the slop out of the track, you increase the minimum radius requirement to a more realistic value. The payoff is in much improved appearance, and derailment- and rattle-free tracking though turnouts.

    Final tip is to match the wheel profiles and back-to-back to track standards. In HO, code 110 wheels are designed to be used with NMRA spec track and turnouts. Code 88 wheels (often sold as "fine scale") look much better, but tend to rattle a little going through NMRA spec turnouts. Code 64 wheels (prototype width) will not run on NMRA spec. Track needs to be laid to P87 spec, where it will work very well. Track and wheels are an integral system that need to be matched to each other.

    There is lots more on this topic in the archives of the Yahoo Handlaid Track Group (handlaidtrack : Hand Laid Track)

    my thoughts, your choices
  3. Nomad

    Nomad Active Member

    Fred, thanks for replying.
    A caution to narrowing the gauge - the narrower the gauge (which also narrow the flangeways at the frog), the bigger the minimum radius required by the rolling stock.

    When you said this, were you referring to turnout radius, or curve radius too?

  4. Biased turkey

    Biased turkey Active Member

    I don't worry too much because I never had a single derailment caused by an out of gauge turnout, and guess what ? I use Atlas N scale tracks and turnouts. All the derailments I had were caused by my own fault: wheels not set properly on the track or turnouts set in the wrong direction.
    I think we have to take what the guy from says with a grain of salt. After all he is in the business of ... selling turnouts.

  5. pgandw

    pgandw Active Member


    I was referring to both the curve in the turnout and curve radius. Steve Hatch (Railway Engineering) admits on his web site that gauge widening would be needed on radii less than 18" in HO. Most flex track is wider gauge than NMRA minimum, so it's not an issue.

    In fact, just the opposite applies to me - the wallowing of my 0-4-0 (and even 4-4-0) steamers is not pretty on typical flex track. So when I hand lay track, I follow Mr. Hatch's recommendation of gauging right at the minimum NMRA spec. I operate 1890s and earlier equipment, and nothing more than 50ft or so long, so 18-22" radius curves at minimum gauge works fine. Keeping the gauge at minimum also allows far better operation of the improved-looking code 88 wheel sets I am slowly migrating to.

    Someday, I'll likely take the plunge to Proto87. But for right now, the thought of having to find/make/buy and install all new drivers for my locomotives, including my favorite Shays is enough of an obstacle to keep me from making the leap.

    For Biased Turkey - Until you have seen a Railway Engineering turnout, don't knock it. They are essentially beautiful custom-made hand-laid turnouts. Having your models roll through turnouts with at most a very faint click is not common with commercial turnouts in HO - I can't speak for N. And the pictures I have seen of Steve's HOn3 layout are pretty incredible - they tell you how much of a craftsman he is.

    I am glad to hear you have no derailments with your commercial turnouts in N. In HO, there are typically a couple of engines, especially steamers, that will find problems with almost any make of commercial turnout. The disparity between NMRA wheel and track gauge is but one of the causes of the derailments.

    Again, we each make our own choices as to how carefully we are going to follow prototype practice. I'm just thankful that there are suppliers and published methods that allow a non-craftsman like me to bring my track close to the same scale fidelity as the beautiful new plastic locomotives being produced.

    yours in training
  6. Nomad

    Nomad Active Member

    Thanks again Fred. I am considering building my own turnouts again, so I hope you won't mind more questions later. When I made them before I had not heard about the tighter gauge of track. To me it makes a lot of sense.

  7. Russ Bellinis

    Russ Bellinis Active Member

    Fred, I haven't started my home layout yet because my wife and I are living in the spare bedroom while a contractor is remodeling our master suite. Once the remodeling is complete and we move back into the master suite, I'm going to build a "L" shaped switching layout 7'x9' featuring the L A Junction Railroad in the 1990's. I've already bought Micro Engineering code 55 flex track, and planned to handlay turnouts with code 55 rail to save money. Reading this thread and the Railway Engineering information was the first time I realised that the NMRA standards for track gauge are too wide. I still intend to use the ME flex track and handlay my turnouts, but I now have a question as to what gauge I should lay the turnouts. If I lay the turnouts to the narrower standard suggested by Mr Hatch, will I have problems with the ME flex not matching the turnouts? Should I lay my turnouts to the NMRA standard and then tighten the guard rails to eliminate derailments? Should I handlay a short section to gradually narrow/widen the gauge to transition from the ME flex track into and out of the turnouts. I was going to send you a p.m., but thought your answers to this question might be helpful to others as well.
  8. Nomad

    Nomad Active Member

    Thanks Russ, That is something I did not think about. Glad you posted this.

  9. pgandw

    pgandw Active Member

    Your last suggestion would be my preference, and what I do whether I'm using flex track or handlaid track. I just don't like avoidable rail joints close to the critical parts of turnouts. Just extend your turnouts a couple of inches beyond the points and frogs and all will be great.

    To me, using full length pieces of rail for the stock rails through turnouts is one of the beauties of handlaid turnouts. You can't tell where the turnout begins and the track ends; it all "flows" together. You can even get 2 turnouts in a compact arrangement using the same piece of rail for one of the stock rails in both turnouts.

    IIRC, you'll find the ME flex track to have a narrower track gauge than the Atlas. Check it with calipers to be sure what I'm saying is correct. There will be only a few thousandths of an inch at most to correct from your turnouts to your ME flex track - you can probably correct with a few file swipes on the inside of the railhead at the track joint, if need be.

    Finally, a tip for both handlaid and ME flex track - pre-bend the rail. I use a plywood template cut and sanded to my most common radii to bend my ME track against. It even has my standard transition at the ends of the template so I get smooth curves with the ME track. Don't hesitate to cut off the last inch or two that you can't get a smooth bend into. In the past, I have pre-bent my rail (code 70) for handlaid track by hand and eye. Next time, (we are in the process of buying a house and moving to Colorado Springs over the Summer) I will try a rail bender from Fast Tracks for smoother curves. Again, cutting off the last inch or so that can't be properly pre-bent is essential for smooth curves through rail joints.

    If you do the pre-bending, you don't even need rail joiners for either ME flex or handlaid track. Just spike or glue the pre-bent rail/track in place and it will stay. No rail joiners saves the hassle of notching ties to avoid vertical bumps at the joints. It does require, however, a wire jumper or feed to every rail section (not a bad thing from an electrical point of view).

    Note that the no rail joiner method does NOT apply to Atlas or other manufacturers' "springy" flex track. Being able to do without rail joiners on curves depends on the rails holding their pre-bent curve on their own. Atlas flex track does not do this! The only way I know of to get a smooth joint on a curve with Atlas flex track is the soldered rail joiner/joint method.

    You got my fingers itching to lay some track again. Right now, I'm arguing with the family for the bigger basement bedroom as my office/train room (16x14) on the house we just contracted for.

    yours in training
  10. Russ Bellinis

    Russ Bellinis Active Member

    Thanks Fred. I haven't checked it, but wondered if ME track might be closer to scale than the NMRA standard. As far as soldering jumpers between sections, one thing that was "drumed into my head" when I joined the modular club 15 years ago or so was that rail joiners are for mechanical connections only NEVER to be used for an electrical connection! In fact the club's standards call for a 2 inch set back with 4 inch joiner tracks instead of the NMRA standard 9 inch Atlas snap track because all but the smallest steam engines or "critters" will bridge a 4 inch joiner track, but not a 9 inch snap track, so we don't even need to rely on the rail joiners between modules to carry electricity to the trains.

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