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suggestions for creating a drop in atlas under table switch machine

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  • Member since
    July 2018
  • 285 posts
suggestions for creating a drop in atlas under table switch machine
Posted by IDRick on Monday, December 2, 2019 5:26 PM

Being an old guy with bad knees, I don't want to spend excessive time under the layout.  Mel suggested in a different thread to consider installing atlas undertable switch machines from above rather than below.  Hat tip to Mel, always a thinker and willing to share ideas!  :-)

I like this idea have been pondering possible ways of doing this.  The layout has a 1/2 inch plywood sub base with 1 inch of extruded foam on top.  Possible process:  

Step 1 dig out a 1"x4" rectangular hole in the foam down to the plywood base. 

Step 2 Drill a hole in the sub base plywood for wiring to SPDT (center off, mom).

Step 3 Cut a piece of half inch plywood that fits in the 1"x 4" rectangular hole

Step 4 Cut a 1/4" x 3/4" horizontal slot in the plywood for the SM rod

Step 5 Cut strips of 1/2 inch extruded foam and attach inside the hole (serves as a ledge to hold the plywood in place and gives room for switch machine thickness)

Step 6 Glue cork roadbed to the top of the 1"x4" plywood (leaving a gap for the SM rod)

Step 7 Insert SM turnout rod into turnout and attach turnout to the cork roadbed

Probably more steps (or different order) may be required.  Thoughts, a reasonable solution for a drop-in and removable undertable switch machine?

Any suggestions on which products to use to attach SM to plywood and plywood to corkroad bed??  I'm thinking of trying double sided tape to hold the switch machine to the plywood as it's helpful to have some working time.  Good idea or not?  If so, which one?

Thanks for any advice you can give me!

Best,

Rick

  • Member since
    January 2009
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Posted by RR_Mel on Monday, December 2, 2019 6:25 PM

I haven’t tried to do it, just sounded doable to me.  I would try to just position the switch machine under the turnout and use a small dob of silicon glue, I use Amazing Goop.  A small enough dob so that if I doesn’t work correctly it can be removed.
 
I would think just removing the ½” foam would be enough for the switch machine to clear the plywood.
 
The round throw arm gets thicker closer to main throw arm, make sure it can operate the moving tie.  Maybe attach the cork to the ties then the switch machine to the cork.
 
Take pictures!!
 
I haven’t been able to crawl on my knees for over 10 years.  Anything that helps is great.
 
EDIT:
Before I would go with all the different things you suggested I would just use a 1" hole saw to make room for the switch machine in your layout plywood to clear it.  One hole on each end of the switch machine then a saber saw for the middle.
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
 
  • Member since
    February 2002
  • From: Reading, PA
  • 26,630 posts
Posted by rrinker on Monday, December 2, 2019 7:22 PM

 The Atlas machines are thin enough to fit in the 1" foam. So you would use a thin piece of styrene under the turnout, then attach the switch machine under the styrene. Hollow out a section of the goam under the turnout to make room for the switch machine. Install turnout.

 If you are using cork or other roadbed, put that between the styrene and the turnout. 

 After hollowing out the foam, drill a hole for the wires to drop through.

 A couple of layouts ago, I mounted Tortoise machines from the top side of my foam-based layout, but it had no plywood. I sttached the Tortoise to a square of perf board, and then used a router attachment on my Dremel to route out the foam to the thickness of the perfboard, and used a knife to punch out a block through the foam big enough for the Tortoise to pass through. Drop this assembly in place, it was flush with the surrounding foam. Roadbed over top and then the turnout. 

 

                                     --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 18,556 posts
Posted by MisterBeasley on Monday, December 2, 2019 9:15 PM

As an experiment, I glued an Atlas machine to the bottom of a turnout, bent the throw bar appropriately and wired it up.  It required a notch in the roadbed and maybe a bit in the underlying foam.  I did not glue down the turnout.

I never had any problems with this assembly.  To be honest, it was only used for a couple of little-used spurs, but the Atlas has been an enduring machine for decades so failure is uncommon.

This, of course, gives me another handy excuse to recommend  a capacitive  discharge circuit to protect your twin-coil machines.

It takes an iron man to play with a toy iron horse. 

  • Member since
    July 2018
  • 285 posts
Posted by IDRick on Tuesday, December 3, 2019 10:45 AM

Thanks for the replies!  Always helpful forum!

I have atlas #65 undertable switch machines.  As Mel pointed out, the round throw rod is not a single round dimension, rather it flares out on the bottom 1/2 inch.  The possible solutions are: drill out the mount hole in the turnout, carefully trim the throw rod to correct diameter, or mount the switch machine at least half inch below the track.  IMO, the latter is preferable to avoid a "miscut" that weakens the throw rod or damaging the turnout tie.

The layout has 1 inch foam on top of 1/2 inch plywood.  Clearly there is adequate depth of foam and probably easier to excavate the hole to the plywood rather than trying to hit an intermediate depth.

I have some surplus 1/2 inch extruded foam and could cut into small strips to mount in the bottom of the rectangler hole.  This process will center the switch machine and keep it from dropping too deep in the hole.

My plan would thus have the following "sandwich": turnout, cork roadbed, 1/2 inch plywood, switch machine, 1/2 inch foam, and sub-base plywood.

Final dimension, the throw rod would be mounted ~3/4 inch below the turnout.  I'm looking forward to trying this out!  If it works well, I will have a method that requires minimal excavation, is easy to replicate (same dimensions on all wood pieces and 1/2 inch foam) and is hidden under the cork roadbed!  :-)

Yes, I will purchase a circuitron snapper if I decide to use this method in the future.  Right now I'm just playing with the idea using scrap foam and plywood!

  • Member since
    January 2009
  • 4,238 posts
Posted by RR_Mel on Tuesday, December 3, 2019 11:26 AM

I think you’ve got it.  Do it to it.  Take lots of pictures!!  Post the pictures!
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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