Feeding the Frogs I

Overall I have been happy with how well my engine runs on LSR’s track, but there is one recurrent problem that I want to mitigate before I start placing structures and scenery permanently on the board.

My turnouts are all Electrofrog, which means they route power across the length of the turnout, without any gaps to account for polarity. Because of this, different sections of the track switch polarity based on which way the turnout is switched.

This is why, when laying track, I added plastic insulating fishplates on the inner rails where track diverges. This creates breaks in the rails to prevent crossed polarities, which would shut the layout down.

The problem with insulating that section of track is that it completely isolated the part of the turnout known as the “frog,” which is the vaguely X-shaped meeting of inner rails. As a result, the frog only receives it power from the points, which move like windshield wipers from rail to rail to route the trains.

When the points don’t press hard enough against the rails, or when the smallest amount of dust, grime, or oxidation builds up between the points and the rails, the frog doesn’t get any power, and the trains stop on the “dead” frog because they aren’t getting power in turn.

The problem, though, is that the frog needs to switch polarity depending on which way the turnout is switched. Initially, I planned to eventually purchase a “hex frog juicer” which works with DCC controls and which powers six frogs and switches the polarity automatically.

I didn’t realize until recently that the SMAIL switch motor I installed for each turnout is capable of powering the frog and switching the polarity using a built-in SPDT switch. However, this will require more wiring and probably a lot of trial and error.

As shown in the diagram, each turnout needs three feeders added and connected to terminals 2, 3, and 4, which lead to one of two SPDT switches inside the SMAIL machine, as shown here:

Terminals 5, 6, and 7 also lead to an SPDT switch, often used to trigger signals.

Over the weekend, I connected terminal 4 on each SMAIL to the frog itself. It isn’t powered yet, though, without the added feeders from terminals 2 and 3. But it’s a start! I used lengths of green 22-gauge wire and soldered them to the outside of the rail between each frog-and-point assembly.

Now to add the outer feeders to the stock rails, which will complete the SPDT circuit. There will be mistakes made, though, because which wire goes to which side of the track will be dependent on which way the turnout is facing.

I will update after I’ve installed and tested one or two.

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