I have been designing a layout for some time using SCARM and prototyping with track on the floor. I ran into many problems that the prototyping did not match SCARM (I did a thread “Reconciling SCARM Design to the Actual Layout”). Also, some of the stuff I built on the floor did not look right.
I am using tubular track and much of it is O54. I recently discovered some variation in the size of the track that explains the problems that I have been having. I was laying out track on top of Homosote to mark it for cutting. It looked wrong and came out non symmetrical. I started measuring the track. I measured the center rail using a tape so it would follow the curvature. I used the same method on each piece and the same tape. The standard length is 10 ½” (not including pin). SCARM thinks they should be 10 ½. I found some that were 10 3/8 and some that were 10 11/16. This is enough variation to really throw things off. When I got all pieces of the correct size on the Homosote, it came out correctly.
I have about 200 O54 pieces. About 25 were too short and another 25 were too long. The problem is that they were randomly mixed in with the correct ones throwing off circles and return loops subtly.
All the O54 is Lionel which came in 3 tie and five ties at different times. All the bad pieces are the three tie version. I had added two ties to the three tie pieces for consistent appearance thus reducing my perception of the problem. I did a thread some years ago asking about the 3 vs 5 tie variation without conclusion.
This is a very annoying problem. I have lost a tremendous amount of time dealing with the issue and some of my design work is off. The good news is that the variation is not so great as to blow my overall design concept. I am just starting bench construction and I can make small adjustments in the size. The pieces that are too long can be cut down so I think I have enough good pieces to finish construction. One waste is that in the prototyping process I cut some pieces to fit and they likely will have to be redone. The randomness of these pieces in my prototyping make it had to sort out.
I am kicking myself for not recognizing this sooner. It did not occur to me that the manufactured pieces could be this far off. I only found this when I went to put together a circle to trace on the Homosote and I could not make a circle due to the number of incorrect pieces I was using.
Maybe I can save someone else from going through this problem.