Tuesday, July 2, 2024

Update on switch machine installations

On my layout, nearly all switches are hand-thrown (as would be such switches on a prototype rural branch line like I have modeled). But in a few places around the layout, where manual access is not convenient, I have had to provide an alternative (for more discussion on this subject see: https://modelingthesp.blogspot.com/2019/02/powering-turnouts.html ).

The one place I have powered the switches is where the track runs right behind some industries, making it awkward (and potentially damaging to structures) to hand-throw the switches. But this installation, in the track between my towns of Ballard and Santa Rosalia, has been involved with some trackwork difficulties. 

When the original track switches were in place, I could operate them easily with the MP1 machines, because the throwbars of the switches were not very close together. I described this installation in a previous post (you can see it at: https://modelingthesp.blogspot.com/2024/04/trackwork-wars-part-11.html ). Here is how it looked:

But when I had to replace these two track switches, a variety of track conformation issues caused the throwbars to be located closer together than before. This in turn meant that the MP1 machines would interfere with each other if the two actuating rods were both perpendicular to the track. As a compromise, I located the right-hand MP1 at more of an angle to the track.

This does require a little longer throw, easily accommodated in the MP1 because the throw distance is adjustable. But there was also another effect, greater friction, and sometimes the machine would only throw the switch part way. I was pondering what to do, when the track issues got worse.

The machines had to be disconnected and moved out of the way when the switch-gauge shrinkage issues were being corrected, that is, by restoring the track gauge (see this post: https://modelingthesp.blogspot.com/2024/05/trackwork-wars-part-14.html ). I then decided to try moving the two machines to be more symmetrically oriented to the track. This essentially involved enlarging the throwbar “trenches” somewhat to the left of the existing trench for each machine, preparatory to relocating the machines.

When installed, the two machines now had a nearly perpendicular throw direction, relative to the track axis, which quickly proved to be a much better mechanical arrangement. 

Next, as previously, the tubes over the throw rods (visible above) will be “buried” with paper mache to conceal them. But the important part, at this point, is that both of the two MP1 machines now operate properly, with the  more nearly perpendicular throw angles.

Tony Thompson

2 comments:

  1. Why not have the two MP1's face each other? In other words, rotate the left one (in the photos) 180 degrees?

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    1. You read my mind! Your suggestion was Plan B.
      Tony Thompson

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