New Throwbar for Central Valley Turnouts

wp8thsub's picture

I started on a new industrial spur this week.  I chose a Central Valley (CVT) turnout kit, partly for the challenge of trying a new throwbar idea.  This is HO scale.

I like CVT turnouts.  They deliver smooth operation and look good.  A few aspects of the kit design and assembly procedure leave something to be desired, however.  I ignore the foil strips in favor of hard-wiring the closure rails.  I gap the closure rails at the edge of the "frog block" to prevent back-to-back wheel shorting.  I also assemble a soldered frog point. 

The only really annoying components for me though are those for the throwbar.  The kit design is clunky, prone to mechanical interference, and quite unfriendly for use with a Caboose Industries ground throw.  Fortunately, as I discovered, it's also very easy, quick and cheap to replace with something that works far better.

The new assembly is shown above (also note the decoder wire feeder attached to the heel of the point; there's a corresponding feeder on the opposite point).  I used the following steps:

  • Glue the tie strip down (I used acrylic/latex sealant), avoiding getting any glue under the headblock area.  I glue in one piece to keep everything aligned.
  • Once the glue dries, cut the headblocks out of the tie strip and replace them with new wood or styrene headblocks.  I used 6"X8" scale stripwood, which matches the kit ties closely.
  • Cut a new throwbar from .080" black styrene (available from Evergreen).  The exact dimensions aren't critical; just ensure it won't interfere with the headblock ties but keep as wide as possible for strength.
  • Use the kit throwbar to measure for holes into which the "tabs" under the cast points will rest.  I used a 1/16" drill bit, which is about the right size once I use a square jeweler's file to re-shape the holes to fit the square tabs.  I also drilled a 1/16" hole for the ground throw.
  • Test fit the throwbar and adjust the holes as necessary around the tabs.
  • Once everything works as intended, add a cover plate to keep the point rail tabs in place.  I had a piece of thin gray styrene which I cut to fit, and glued atop the throwbar with styrene cement.  I also glued on a piece of joint bar from the kit to approximate a tie rod, and to break up the smooth surface of the plastic cover.

That's it!  Now proceed to adding the remaining kit details as desired.

Note that I'm not much of a fan of PC board for throwbars, and I really do like the kit point castings.  The above procedure allows me to readily use the points, while creating a durable assembly with no solder joints to fail.

Comments

That looks nice and seems

That looks nice and seems real easy to make. I have used P87 stores solder able throwbars on mine and I also do the decoder wire feeds too. Before using the P87 throwbars I would file the tabs off the points and solder a brass pin to them and use strip wood for the throwbar. Some have split and loosened. I changed to styrene strip for awhile.  I also make my own frogs on a home made jig then cut it short about 5/8 of an inch long. With .015 styrene for gap fillers and the frog details they work great. Never a need to wire the frog even for my little brass 0-4-0T.

           Pete

Joe Brugger's picture

Interesting

Do you have a good guess on the longevity of styrene?  Seems like Delrin might be a good choice, too, assuming it could be found in strips or sheets.

wp8thsub's picture

Longevity

Joe - I've had good luck with thick styrene for throwbars.  Another local layout has a yard ladder where all the handlaid turnouts use styrene throwbars made of thinner material, and I'm aware of only one that has broken in the last 20+ years despite heavy op session use.  None of mine have been around that long, but I have no failures to report.  Engineering plastic like Delrin would probably be even better as you suggested.

Rob Spangler


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