Table Expansion - Track Plan and Track Spacing Help

SCARM appears to use 3.5" for roadbed width, regardless of track brand, for both the 3D view and the roadbed when you turn on Roadbed in settings. If you turn on the Center Rail in settings, you'll find your spacing for the center rails along the top of your design is less than 3.5" center-to-center. That appears too be close, especially with the curves you have, and engines are likely to hit each other as they pass. That's acceptable spacing in yards where speeds are slow and tracks are straight. 4.5" is the recommended minimum for mainlines and that depends on engines being run. Large engines can require 6" or more because of the engine overhang. Plus, your tracks are very close to the edge and if there's an accident, there's a good chance something will end up on the floor.

Here's an alternate configuration that might give you some ideas. I also included a photo of your original so those without SCARM can see it.

A few things that I’ve learned using SCARM …

You’re correct in guessing the software isn’t 100% accurate.  

SCARM is a good way to estimate how the track will look in a given amount of real estate.  It’s especially helpful when estimating how much curve (036, 048, 060, 072) will fit.   You won’t know for sure how things will work until the track hits the table.

There is some wiggle room with Fastrack.  You can flex everything a bit to close gaps.  Don’t sweat getting everything to connect perfectly in SCARM.  The 1 3/8 and 1 3/4 pieces are handy to have to fill in gaps.

Even though you might not have big engines, using 072 switches helps reduce the space between the tracks when building a crossover.

You might consider using a crossover to extend a siding into the center of the layout like I did.  It opens up the possibility to more storage for the outer loop.

Are you limited to 4' width?  If you could go 5' x 10' instead of 4' x 12', it would be much easier to put an O48 FasTrack loop outside your O36 loop.  This keeps your trains more away from any table edge and allows sufficient space between tracks to avoid damaging trains passing on curves.  Generally, O31 inside of O36 only works if you stick a decent size piece of straight track in the middle of each O36 half-circle.

Chuck

@PRR1950 posted:

Are you limited to 4' width?  If you could go 5' x 10' instead of 4' x 12', it would be much easier to put an O48 FasTrack loop outside your O36 loop.  This keeps your trains more away from any table edge and allows sufficient space between tracks to avoid damaging trains passing on curves.  Generally, O31 inside of O36 only works if you stick a decent size piece of straight track in the middle of each O36 half-circle.

Chuck

Unfortunately, this is a table that I have under another table, so I'm limited on the width by the upper table. (picture below)  The upper table is 4 x 12 and I need to stay in the same footprint.  That is also why I have those odd "bumps" in the layout I designed, I need to account for the upper table legs.

Once my kids go off to college (many years from now) I'll finally be able to take over the entire basement!

DoubleDAZ / VJandP - thanks for the help, I'm going to play around tonight on SCARM and see what I can come up with. 

That certainly explains things a lot better, so give this version a look. It's still tight in the lower right, so you might have to have a right-of-way. You might be okay running both trains clockwise to avoid front end collisions. Running clockwise lets you back cars on/off the spurs.

And here's one more with a bit more clearance on the right and lower right.

@DoubleDAZ posted:

And here's one more with a bit more clearance on the right and lower right.

Thanks for all your help!  I took your ideas and came up with a new track plan I think I might try.  I have to get all the lumber and build out the table first, then I'll use those measurements to confirm everything will work. 

I created two separate loops that will have their own power source and block sections between them.  Also, I was going to isolate the siding.  This is my first attempt at using block tracks, so I'll have to start doing my research on that now.

I know I made some spacing tight, but I think it will work and I have room to make small adjustments in the design once I have it all laid out. Let me know if you think this new option has any glaring mistakes.

Sorry, I've been packing for a trip, so I just got to this. I still think the tracks are too close on the right side at less than 4", so I'd suggest the changes I circled in Red to move things over just a bit. Basically I moved some 1 3/4" tracks around.