I’m building a layout that has open grid benchwork topped with 1/4" plywood, and 2 1/2" of rigid foam. Track is all one level, but I wanted be able to have terrain both above and below track level. Turnouts are ground throws with the exception of two crossovers which I am controlling with Walthers switch machines.
The actuator wires on the switch machines are too short for sub-roadbed that thick, so I replaced them with 18 gauge music wire. Per the instructions the hole that the wire comes through should be 3/8". Installed the first two machines and the crossover. When I attempted to throw the switches, the servos engaged, but the points didn’t move. I increased the throw distance of the wires. This helped with one side, but the points weren’t snug against the rails. The change to the other end was minimal.
Because of the thick sub-roadbed do I just need to make the hole in the sub-roadbed wider so the wire can travel more? Or am I missing something?
I have Walthers machines and I also had to change the wires to make them longer.
I think you’re on the right track with enlarging the holes. It may be the wire is bending after contacting the side of the hole just enough to not move the point.
I would enlarge the hole in the plywood quite a bit, and dig out more foam. You can always make the surface hole smaller when you’re ready to lay ballast.
I always say that working through foam or plywood is easy but find working through both is a pain.
What you can do is cut a little square of the plywood out underneath and take a boxcutter and with a permanent marker put a line at 2" and cut a bunch of little squares out of the foam underneath so it looks like a grid. They will only be cut to 2 inches, not all the way through. Once you have all the little squares cut they will pop out quite easy and break at the 2" depth. Then take the square of ply you cut out and glue it in the hole and mount the unit.
the music wire come up between nearby track ties and pivots the L-shaped wire to move the throw rod.
you just need to drill the hole down from the top after the turnout is in place. The pivot at the bottom can be at any angle. the dpdt switch is optional.
Here is an alternate view that goes against current thinking. Don’t use the foam. Built you layout with true open grid construction, only put wood subroadbed and a roadbed material (cork, homasote) where track and level structures go. Then use hard shell scenery to get your below track level scenery rather than carving foam.
That way your switch machine wires only have to pass thru the sub roadbed and cork or other roadbed you use, typically only about 1".
Problem solved by going back to previously tried and true construction methods.
Other thoughts on turnout control. Since there are no truely scale practical ground throws, I use slide switches like Greg’s diagram.
But I mount them right in the roadbed next to the turnout throwbar, or in the case of yards, along the layout edge with throw rods running under the track.
In my opinion they are better looking than oversized Caboose ground throws. They provide electrical contacts for power routing and frog power, and are easy to operate with the same small tools used for manual uncoupling.
So this also requires that track be mounted on firm materials, not foam…
I use the same type of wire V spring show in Greg’s drawing.
I use manual turout controls where they would be manual on the prototype and have switch machines on CTC or tower controlled turnouts.
