Back to Back Fastrack Wye?

David, first of all, I like your track plan.  It includes lots of possibilities for operations.

I don't currently own any large steamers requiring 0-72 curves.  But, I have done testing with scale diesels running at very high speeds through 0-72 FasTrack Wyes configured with S-curves similar to the one you're contemplating, with no issues.  Of course others may have different experiences.

You might consider setting up a temporary test track that includes a scaled down version of any sections of your plan with which you have questions.  That should help you decide whether there are tradeoffs you are willing to accept or not.

David;

I have back to back Fastrack wyes leading into my engine yard. Past the wyes are a series of O-72 switches. I primarily run scale engines in and out of the yard (up to and including a VisionLine BigBoy) with no issues to date.

Obviously a trade-off, but you could eliminate one of the track lines across the bottom of the layout and move things down to create space for a straight between the back to back wyes.

@SteveH posted:

David, first of all, I like your track plan.  It includes lots of possibilities for operations.

I don't currently own any large steamers requiring 0-72 curves.  But, I have done testing with scale diesels running at very high speeds through 0-72 FasTrack Wyes configured with S-curves similar to the one you're contemplating, with no issues.  Of course others may have different experiences.

Yup, I'm with Steve.  When I had my FasTrack setup all my steamers & diesels (scale and traditional) handled the O72 curves/switches (with S-curves) full speed... no problem.  The only ones that could not are the circa 2003 K-Line GG1(s) which are ridiculously (more accurately, insanely) fast runners.

As with most questions like this, you are thinking of "going against the grain" of most track planning advisers.  The usual recommendation is to avoid "S" curves of any radii or diameter because of the potential for problems they cause.  That usual advice also states that if your plan requires an "S" curve for some necessity, then at least try to insert some straight length between the two parts of the "S" curve, which straight length is at least as long as the longest piece of equipment you might ever run.

As I "read" your plan, the switches that create the "S" curve are intended to allow trains running either direction from your inner-most oval to transfer to your outer-most oval so that again they can run in either direction.  I further have to assume, because they are not in your plan, that you will have pop-up hatches in the middle of both dog-bone loops and in the middle of your smaller, centered loop at the bottom.  I can almost guarantee you that if you leave the "S" curve built in, you will be using those hatches a lot to fix derailments.

You might also want to read up on yard leads and not fouling the main lines while working those sidings.  As now designed, to do any switching work at the bottom of your plan, the oval becomes useless as a main line.

Finally, while pictures are useful for those that don't have your software, attaching your plan "files" would make it easier for the design experts here to show you suggestions.

Chuck

I ended up with S-Curves into the yard to maximize the space and still maintain O72 or greater curves.  I've run everything up to and including the Vision Line Big Boy in and out of the yard with no issues.

I like the idea of setting up a test bed with the configuration you're considering and see how it works out.  With Fastrack, it should be quick and easy to plug it together and run some engines and cars through it.

Thanks so much for the thoughts on this! I should perhaps add that this is a floor layout, though it resides in an area of my attic where the attic floor is raised 34” because of a cathedral ceiling below. So the operator stands in front of this raised area (bottom of the picture) with the layout in front of you at roughly table height. So, needless to say, there are no access hatches possible. I must climb up onto the layout and bend or kneel down to fix derailed trains. That’s why it’s shaped the way it is.