Maximum length for throw rod for Tortoise?

Model Railroader Layouts and layout building
1

I need to mount a Tortise about 4" below a turnout. Has anyone had any experience with that long a throw rod?

Thanks,
Chuck

2

Yes, I’ve mounted Tortoise machines with throw rods up to 6 inches long by using piano wire. The fulcrum can be adjusted to compensate for such a long wire. The main thing you must watch out for is that you don’t put so much pressure on the wire that it bounces back in the opposite direction off the side of the hole. A second person who understands what you need to do to help get things adjusted by watching from the top as you work underneath is advisable.

3

Thanks, that’s good advice.

4

Replace the throw wire with a heavier (thicker) piece and adjust the fulcrum and or make the hole through the bench larger such as 3/4" and it should work.

5

You can also place small copper tubing over the wire so you can get even more pressure.

6

The most important thing is to make sure there is sufficient clearance for the movement of the wire connecting the machine to the points. The thicker the wire, the less “bend” and thus less the size of the necessary hole, but you don’t want the wire to be unnecessarily heavy either. I’m sure it is workable, but be prepared to experiment.

7

I’ve had turnouts over 6 inches above the top of the tortoise. I was able to get the throw rod so ridgid that the tortoise couldn’t complete it’s throw. It stalls in the exact same way that it does when it hit’s it’s throw limit. The contacts work correctly too.

Tortoise’s have very high force capabilities and a very reasonable 20 mA max current. This makes it easy to use almost any op amps and other logic circuits to directly operate them. The contacts in swtiches will last a very long time too. Since motors draw the most current when stalled, tortoises are designed to be normally stalled. Extremely inefficient but low power usage. The current drops down below 5 mA while operating.