Thursday, June 18, 2015

Helix design

When I decided that I would need a helix to do what I wanted to do on this layout I studied everything I could on the Internet and examined first hand any helix that I could.  The room that I built in the back of my garage is a 20 x 10 ft rectangle but has a 2 ft bump out in one corner for part of the helix.  The net space set aside for the helix is 42 x 42 inches.

I really liked the idea of using all thread rods to support the helix because it would allow me to experiment with some different grade adjustments plus it offered the best access to the tracks.

My design uses 90 degree curved sections of 1/2 inch plywood that are 4.5 inches wides.  The radius on the outer edge of the curved sections is 20.5 inches.  Between each section a pair of splicing blocks hold the sections together and attach to 3/8 inch all thread rod.  Two 8-32 screws on each side of each section will secure the splice blocks to the curved sections.

I found that I could get 10 of the curved sections from a 4 x 4 sheet of birch plywood.  After making the first one I marked it as master and used it as a template to draw the others.

The splicing blocks are made from scraps of the sheet that the curved sections were cut from in between 1/4 inch thick birch plywood material.  The overall size of these assemblies is 4 inches x 2 inches.

Here are the results from a single 4 x 4 sheet of plywood.  The curved sections on the left have been painted. All sections will be painted prior to assembly.  This is a start, my plan is by doing some of this now, I'll be able to go right into assembling the helix after the yard is completed and installed.

Wednesday, June 3, 2015

Removable bridge for the upper staging yard.

Besides the brass bridge that I built last November for the loop on the upper line to pass over the loop on the lower line, there was going to be another bridge needed to bring the front end of the loop back over the yard ladder of the lower yard.   This curved bridge was built of tempered hard board.  I thought that it would be great if the bridge could be made removable in case that yard ladder ever had to be worked on.

Here is the completed bridge installed.  The tempered hard board worked out really well in this off scene application where sturdiness was the most important feature needed.

Here is the bridge removed to access the lower yard ladder turnouts below.  It only takes a few minutes to remove or re-install the bridge.

Since I had been happy with the results of using small sections of PC board to make the rail gaps, I decided to try to use that to make solid ends for the track on the bridge and for the approaches to the bridge.

For more details on how I work with this material, see the post Staging yard track gaps.

In this photo one of the screws that hold the bridge in place can be seen.
As the section of track on this bridge is not mechanically connected to the main track, feeder wires soldered to the bridge track pass through a hole and connect to the main feeder.

At this point the road bed is in for most of the upper yard and enough track is in on the return line so that this bridge has been thoroughly tested.  Some more turnouts have been built and track laying in the upper yard can proceed soon..