Ross Switch size numbers vs Atlas

Smaller switches will work the smaller curves, This was my Atlas original layout with O54 outer loop, O45 inner loop.  All but one switch was O54.  20 years ago Atlas had a design software. Some of those software packages are still around. Not Atlas.

First off, the "old" free Atlas track planning software was just a licensed version of SCARM that only included the Atlas track library.  SCARM is still available, includes Atlas and a lot of other track libraries, and can be freely used with only a track piece limit of 50 pieces, if I recall correctly.

Second, when choosing any switch with a track curve designation (e.g. O27, O31, O36, etc.), the only real issue is how well the curved and straight sections will fit into your plan.  Typically, for example, an O27 curve (and, I believe, an O31 curve) only requires 4 pieces of track to make a half-circle.  So, if you substitute either an O27 switch OR an O31 switch for one curve piece in your O27 or O31 half-circle, you would have little to no problem.  HOWEVER, if you tried to substitute an O54 or an O72 switch in your O27 half-circle, you would have a "half-circle problem" because the O54 size requires considerably more pieces to complete a half-circle.  It's more about the degree of curvature running through the switch than the described diameter of the half-circle.

As a further example, search for track easements on the forum.  You will find, for example, that some people build half-circles of O54 diameter starting and ending with 1 O72 piece of curve to create an "easement" into the O54 curve, with very little difference between a full O54 half-circle and an "eased" O54 half-circle.  Again, it's all about the degree of curvature of each piece of curved track, not the diameter.

Hope this helps.

Chuck

I believe deep in the Ross website there are , (full sized?? Show as 78% on my screen??), templates available for their switches.  I could be wrong and often.  IMO, Mike CT. One of the common switches.  Click on the underlined phrase.  Contact Ross, they would probably direct you, or send you the correct template for any switch. 

  Thanks, I went to Ross site and a lot of the pictures did not come up. Looks to me that they go by # like 100,101 and so on, but I didn't see a size like 031, or 045, I did see some 054. I don't thin they have 036 I just don't know what size to use on my layout. I guess I will go with Atlas switches.

031 and 042 are under the Super Line switches on the Ross website. There are pictures.

Download SCARM... it will not take very long (4 to 6 hours) for it to become very useful.  I won't get religious on track/switch manufacturers, I run Atlas, Gargraves/Ross are excellent as well.

Use the largest switches you can.  I have 045, 054 and 072 loops and until today I only had O72 switches.  I have now added four #5 turnouts (switches) which are larger than O72.  Ross makes a #4 that is very popular with the folks here.  Additionally, word to Chuck on the easements... I have O72 curves entering and exiting the O54 loop.

SCARM will help immensely in understanding, creating and visualizing your track plan.

This is what Jan helped me with using SCARM they are all Atlas 036 switches and track.  So wondering if I went with the Ross switches what size would I use?