Designing a "reversing triangle"

Model Railroader Layouts and layout building
1

I am working on designing an N scale narrow gauge railway in rather primitive conditions. The historic record says depots had small rectangular engine seds, ashpits, water supply and a reversing triangle.

Can anyone tell me what a reversing triangle looked like and what to buy to build one.

Thanks

Robin

2

Hi Robin, welcome to the forum. I would imagine that the description is refering to what is genreally called a wye. http://www.nmra.org/beginner/ex_plus.html if you look at this track plan, there is a detail picture of a wye design for a model RR. Basically, it was a way that a locomotive could be turned at the line end to head back forwards on the return trip. An alternative is a turntable, but these require maintenance so a wye was a popular method of achieving this.

3

To build a “wye” like the one Simon’s link shows, you will need …

  • 1 wye turn-out;

  • 1 right-hand turnout;

  • 1 left-hand turnout; and

  • flex track.

It will have to be wired like a reversing loop (and turntable). Exactly how depends on whether you are using DC, or DCC.
(NOTE : you can build a wye that is curved on all 3 sides by using 3 wye turn-outs instead of the ones listed above)

The length of each side of the wye can be any length; but, generally, they were as short as possible while maintaining your minimum curve radii.

Wyes and reversing loops take up a fair amount of room, so were not used in yards/depots where space was at a premium. Where space was too tight for a wye or loop, turntables were an answer.

4

Think of a Wye being like a 3 point turn in a car.

Since its a reversing track, you have to change the polarity someplace. The absolute easiest way to do it is to wire the reversing switch to the tail of the wye, so that when you line the switch, the tail track matches the polarity of the leg the switch is lined for. Its pretty foolproof.

Dave H.