Adjusting Model Train Layout Turnouts And Crossings

Ask any experienced model railroader and he’ll tell you that the most problematic pieces of trackage are the turnouts or switches on his layout.  Where it is true that the frog and guard rails can present problems, this can usually be avoided through proper adjustment.  More often than not, more troublesome problems occur with the points, which are the moveable sections of rail.

If you are new to model railroading you may not know what a point is and the following description will be helpful:  Points are sections of rail whose function is to guide the train you’re running from one track to another.  Characteristically, they are varying lengths of rail that taper off to an almost knife-like edge or point.  This point is then held against the outside rail of a turnout, and the sharp edges perform the function of guiding the wheels away from the stock rail.

This is how points continue to work:  Every normal turnout has two points which are held or separated at a proper distance apart by the throw bar.  The throw bars sole purpose is to hold the point in the proper position, which then allows the train to pass through the turnout in whatever direction it is set.  The modeler can either choose to throw the points by a hand throw or a remote control of some type.

How turnout points are adjusted is the most important issue, and there is more than one adjustment which must be made.  It is important to remember that no one adjustment is more important than another.  You must also be aware that each point must fit snugly against the stock rail when the turnout is thrown in that direction.  If the points do not fit as they should, the result will be potential derailments.  

Having said all of this, model railroaders should also be aware that manufacturers deal with this point rail or stock rail contact in one of two different ways:  They either include a slight notch in the stock rail so that the point fits into the notch, or they leave the rail as it is.  If they opt to do this, they will choose to shape the point rail so that it fits closely alongside the stock rail.

Another important consideration is that the tip of the point should be as sharp as possible, and if it is not, you should then take the matter into your own hands, and sharpen them yourself.  The best tool to use for accomplishing this is a needle file.

One other thing which you should consider is that common dirt or a piece of ballast can work its way between the two rails which will prevent a tight fit.  Because this can occur it is then necessary to check for this issue and take whatever appropriate action is necessary to remove the dirt or ballast.

If the opposite or open point does not maintain the correct clearance between itself or the stock rail this problem will also result in derailments as well.  Your best bet to deal with this issue, and in particular because the NMRA actually doesn’t have a recommended practice for this, is to use the wider spacing flangeway nub on the NMRA gauge, and in so doing the wheels will then clear adequately.  Typically, the commercial type of point rail will vary, and because of this it is necessary to determine exactly how yours are wired.  If your turnouts are wired with the point rails connected to the frog, it means that both point rails are the polarity of the point rail in contact with the stock rail.  

This then means that the open point is the opposite polarity of the nearby stock rail.  An electrical short can occur if there is only a minimal clearance for the wheels receiving electricity from the stock rail because they may brush the opposite polarity point.  If you have a commercial turnout there really isn’t any easy way to adjust the spacing.  The only alternative is to modify the throw bar or create a new one.

Another source for problems is the pivot point of the point rails.  If you haven’t noticed, there is no pivot point or hinge on the prototype.  The prototype are continuous and are actually bent to move the points.  You’ll also discover that just about all commercial turnouts have some form or type of pivot.  A few of these work well, but others do not, and this can cause gauge problems.  The hinge point should be smooth with no sharp ends.  If they are not in this condition the ends of the rail at the pivot point will move somewhat out of alignment.  Once again, this condition can cause derailments.  To correct this you can slightly file the ends of the joint to remove the square end, and doing this will prevent the wheel flanges from catching the corners.  You’ll also have to tighten or adjust the hinge mechanism if the rail movement exceeds the track gauge tolerance.

With that said, you should also know that it is possible to tighten or adjust some hinges.

Additional Tips

For Cork Roadbed-Use nails or spikes whose length is long enough go through the cork into the more solid roadbed.  To avoid surface problems, use care when setting the nail or spike until you’re confident that the slack is not present.  At the same time you want to insure that the hinge cannot pivot easily or in fact that the rail is pulled down.

For Turnouts-If you are using a rivet as a hinge spot, try using track nails or spikes which are long and drive them into the middle of the rivet.  Next, push them into the roadbed to take out some of the slack.  

It is also important to insure that your point rails are of the correct gauge throughout their length when the turnout is thrown for its direction.  The most effective way to check this is with a NMRA gauge.

Another area which can present problems is the frog.  Given that there are no moving parts you’ll only have to insure that everything is secured and correctly adjusted.  Once again use your NMRA gauge to do this work.
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