Bashing a Double Crossover
Using American Models turnouts and crossing
A work in progress..
Click on images for larger view
|I decided to add a double crossover to the layout to add more routing options and because they are visually appealing. The only place that made sense and was physically possible was in a mild curve. Since I am using American Models track and turnouts I went with their products as the starting point. I first made a paper overlay of the existing tracks where it will be located and burnished the track into the paper as a pattern.|
|I transferred the pattern onto a piece of 1/4
inch plywood that will be the roadbed for the crossover. Then I laid out
the proposed track path using the turnouts and 30 degree crossing as
I cut the ties on the bottom of the turnouts so the turnout can be bent to follow the track layout as if it were flextrack. I drilled and spiked the outside turnouts adding the arc as they were spiked down.
|Due to the arc and different radius of the tracks
the crossing will not fall in the middle of the track centerlines and is
offset a bit is closer to the inside track.
I laid out the crossing and determined the cuts in the tracks and ties.
The crossing is inserted into the first two turnouts.
|Here you can see the final trimming of the 30 degree crossing.|
|The second pair of turnout is added after the
crossing is installed into the first turnouts.
The second set of turnouts is spiked down adding the arc to follow the track plan.
|This shows the trimming of the turnouts tracks and
|Here is the project with the trackwork all spiked
|Here is the place on the layout that it will be cut
into the roadbed and track.
|The roadbed has been trimmed and
contoured to match the layout's
existing roadbed. the missing ties have been replaced.. The plywood
roadbed was stained to
match the cork. roadbed.
The crossover is temporarily mounted to a piece of plywood that simulates the layout table top for fitting and testing of the mechanicals.
|I fabricated the throwbar pivot drive shaft that protrudes down through the roadbed and table top|
|The shafts are made from brass tubing
and music wire. The bottom end has a piece of square tubing soldered
onto the inner shaft to hold the RC servo arms.
The shaft is tapped for the servo arm retaining screw.
|The throwbar servo arms assemblies are test fitted with the screws.|
|There is a piece of 1/4" plywood
that is the plate on the bottom of the crossover assembly for holding
the Tortoise drive motor. It becomes a sandwich of the crossover, table
top and bottom plate
The throwbar shaft assemblies are CA glued into the crossover roadbed before the sandwich is assembled. The Servo arms are screwed onto the shafts after the sandwich assembly.
18 gauge wire throw rods are fabricated.
|A plywood mounting cradle is made for
the Tortoise switch machine.
I made a tensioning device for the servo arm on the Tortoise with a couple of springs, collars and a sliding thimble in the middle that screws onto the arm.
|The throw rods are configured in a
balanced system so there are no pushing, only pulling forces.
The action has been tested and is working as expected.
|Block occupancy detectors had to be
A template was made to facilitate hole drilling and crossover placement.
The track mains have been cut and removed.
|The Crossover in place, being tested
Number 4 flathead screws were used to secure the crossover to the layout top from the top side.
|Ballasting and weathering complete.|
|The diamond turned out well and alignment is good.|
|Here is the bottom side. The bottom
plate made installation easy as the alignment was done off the layout.
The Tortoise motor contacts switch the occupancy detector path.
|Dwarf signals are now in place.
All in all, I think it turned out pretty well.
It makes several more options for track routes available.