Thursday, November 24, 2016

Electrical wars, Part 11: better power routing

In my Electrical Wars series of posts, one subject has been old Shinohara turnouts, which over the years have become unreliable in power routing. By “routing,” I mean the point rail–stock rail contact which powers the frog with the correct polarity. These turnouts have a brass strip connecting the point rails at the throw bar, making the points a single unit electrically. There is also a phosphor bronze strip underneath that brass strip, that is very helpful electrically (when it is new), because it contacts the bottom of the stock rails, but as it oxidizes with time, becomes less and less helpful, and is almost impossible to clean. That was the reason for replacing the lead turnout into my yard at Shumala, as I discussed in a previous post in this series, at: .
     One answer is to install separate power-routing contacts under the layout. I have used various kinds of contacts for this, such as a pair of microswitches, or a slide switch, or on some occasions, the contact assemblies from old twin-coil switch machines (the latter was described and shown in an earlier post, which is at: ). All these have one drawback: they require a mechanical connection to the turnout, such as a vertical operating wire, which in turn connects to whatever electrical contact arrangement is chosen. Electromechanical designs like this are not only touchy to install correctly, but also typically require adjustment from time to time, and adjustments can be fussy also,
     A modern alternative is to separate the point rails electrically from each other, then electrically connect each to its adjoining stock rail. That ensures good electrical feed to the point rails as well as correct polarity. But now the frog must be isolated electrically from the points, and a means devised to feed correct polarity to the frog. There are several ways to do that. A purely electrical way is to use a Frog Juicer, made by Tam Valley Depot (see their line of these devices at: ).
     I started out by mentioning problems with old Shinohara turnouts. I decided to try rebuilding one. In a Shinohara turnout, and several other varieties of commercial turnouts, the point rails are connected to each other and to the frog, so those connections must all be changed. My friend Jim Providenza came over to demonstrate how all this can be done. The first step was to cut the rails at the location shown by the red line below, using a cut-off disk in a motor tool, then to remove the rails between that cut and the end of the point assembly (the rails indicated by the arrow just to the left of the line), and finally also to remove the point assembly itself (the arrow farther to the left).

     We started by making the cut shown by the red line. Once that is done, and the adjoining rails removed, the molded-on “spike heads” in the plastic tie strip need to be removed, so they won’t impede the new point rails. The photo below shows this process, which is quick and easy with a hobby knife.

The next step is to remove the point assembly. In doing so, the brass strip that connects the two point rails (at the throwbar) is cut right next to the center rivet on both sides, and the entire throwbar pulled out. When this is done, the turnout now has all the removed parts gone, as shown below.

     The only parts saved from the old point assembly are two of the little stubs remaining from the connection of the points at the throwbar. Shown below are all the removed parts, with an arrow to two of the stubs just mentioned (the other two were already removed). These can be un-soldered from the old point rail, and will be re-soldered to the new point rails in the same location, at the new throwbar location.

     This completes the removal of unwanted parts and the turnout would now be ready to receive the installation of new points and throwbar. I will show the installation of those new parts in a following post.
Tony Thompson


  1. I tried using the the "Frogger" by Fast Tracks and after a year of use they were a real problem. The thin plywood construction created alignment problems with wear on the thin pendulum which moved a "hammer" that closed on the micro-switch. After some study on the problem I tore them out and replaced with the Tam Valley "Juicers." I now used ground throws to throw Fast Tracks switches and the "Juicers" throw power flawlessly.
    I think they are a great product...

  2. Thanks, Harry. After a lot of years not only building new track but maintaining old track, I now have a jaundiced view of ANY switch arrangement that is electromechanical. The Juicer avoids that nicely.
    Tony Thompson

  3. Tony--Great article. Thanks! I have found that the only time the older Shinoharas need rebuilding is when a long wheelbase steam engine rubs the backside of the drivers against the point rail which is not in contact with the stock rail. Otherwise, like when the contact between the point rail and stockrail becomes troublesome or even the Tortoise internal relay fails, just install a Frog Juicer. These things are fabulous. Tam Valley has given us a revolutionary product.
    Steve Hoxie