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: http://modelingthesp.blogspot.com/2016/05/electrical-wars-part-9-contacts-for.html ). 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: http://www.tamvalleydepot.com/support/whichfrogjuicer.html ).
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.