Frogs and Tortoises


For the past few days my head’s been buzzing with AC power (not literally, you understand), DC power, frogs, ‘Tortoises’, ‘Hares’, ‘Wabbits’ ‘Switch-its’ and all manner of things to do with controlling my turnouts under DCC. So much so, that I think my search engine has probably blown a gasket. ‘Information overload’ is enough to make your ears bleed too, at times.

From the very first version of the layout I decided to use Peco Code 100 track with Electrofrog turnouts and Peco point motors. Now, on the latest version of ‘Dales Peak’, I have decided to use Circuitron ‘Tortoise’ slow motion switch machines to operate the turnouts. These have two internal SPDT auxiliary switches, one of which I can use to switch the polarity of the frog. However, before I could make any progress I needed to answer two questions.

1. Changing the polarity of the frog on Peco Code 100 Electrofrog turnouts

Modifying Peco Code 75 turnouts is well documented (cutting jumpers and adding others) but that’s no good if you’re using Code 100 turnouts, like me. After a lot of surfing I finally came across this article on modifying Peco turnouts by Jean-Louis Simonet, which I could apply to my Code 100 turnouts.

2. Using a Lenz LS150 accessory decoder to control Tortoise point motors

The documentation that comes with the Lenz LS150 describes how the accessory decoder can be used to control motorised switch machines but I scoured the internet for any ‘real life’ examples. This research highlighted a possible problem…

The Lenz system uses AC power, which only powers the motor for the duration of the pulse from the LS150. However, the Tortoise is designed for continuous DC power and stalls out at the limit of the turnouts’ throw. Some articles I read suggested that under AC power the Tortoise may not hold the point blades in place permanently.

That’s why I started looking into other ways of controlling the Tortoise, like the ‘Hare’, ‘Wabbit’, NCE ‘Switch-it’, etc. In the end though, I decided to try my Lenz LS150 and see how it performs. Watch this space…


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