non derailing

This might have different meanings in different contexts, but it usually refers to switch wiring.  Many switches (for example Lionel tubular and Ross can be set up for it) have wiring such that if a train enters the switch from the direction that the switch is not lined up with, circuitry automatically throws to the direction from which the train is coming, thus preventing a derailment.

This usually works from the two outside rails.  One rail is ground the other side rail is insulated from ground, but connected to the switch machine.  When the engine enters the switch the first set of wheels and axle grounds the isolated outside rail by connecting it to the grounded outside rail via the axle, thus throwing the switch.

Timing is tight and it is not foolproof, but works pretty well.  You might notice that a traditional O22 tubular switch has fiber pins in one rail to create the short section of track isolated from ground.  There is also a small slit in this rail at the opposite end of the fiber pin.

Bill

You can make the switch, switch, well before the train gets close by adding one or more track and moving your fiber pin to the next length of track, thereby making the track switch while the train is a foot or more before the switch

Thank you that helps

I once tested several MTH Railking switches and their ability to throw running an engine at 120 mph. No derailments. They react so fast that it's amazing.

I do mine electrically but have also used spring wire that allows engines and rolling stock to pass through a closed switch by allowing wheel flanges to push through the closed rail and spring back to closed position hence the term non derailing as to the wheels not coming off the track causing a derailment.

It doesn't even have to be wiring related. FasTrack manual switches have a great performing non-derailing feature that is not just a spring switch, but the points throw all the way over so the route alternates on reverse loops.

@Mike23 posted:

You can make the switch, switch, well before the train gets close by adding one or more track and moving your fiber pin to the next length of track, thereby making the track switch while the train is a foot or more before the switch

might want to stress that IF the 2 outer rails of that 'extra' track piece are not connected then your statement is fine as written.  But with most, at least some, tubular track, metal ties connect the 2 outer rails electrically.  So one needs an insulated track section with the insulated rail on the same side as the switch track that has the dummy pin.  I use 3 metal pins to connect the switch to the insulated track the switch and put the dummy pin on the other end of that piece of track on the insulated rail.

walt