Help with making a Double Main Curves Track

Yes you can use 072s for both loops.  On the outside one, you need to add a length of straight track that is equal to your center to center spacing distance on each end of a 90 degree sweep to offset the curves. If you are doing this with less than 90 degrees, you'll probably need to play with it a little bit to figure out the offset to keep the tracks from converging at the midpoint.

I dont know why there would be an issue with a switch adjacent another switch.

You can’t connect an O-72 switch or any other regular track to the ends of the O-72 Wye unless you first add one of the fitter pieces that come with the Wye or trim the inside roadbed on the switch or track you want to attach. The roadbeds will interfere with each other without the fitter pieces or trimming. Trimming an O-72 switch reduces its resale value, but I don’t believe it interferes with its operation.

What center rail to center rail distance do you want?  5”?  6”?  If we know that, someone can draw an example for you. It does look like you are using Fastrack, so maybe 6”?

Here's what they look like. The arcs have a 6" clearance by adding a 5" and four 1.75" fitters in the outside loop. Note that the loops won't be concentric.

The circled part of the upper Wye shows the fitters without roadbed on one side. Note how the roadbeds of the O-72 switches don't interfere with each other. The circled part of the lower Wye shows how the roadbed interfere with each other and need to be trimmed. Trimming looks better, but it's easy enough to fill by adding your own roadbed.

Using Gargrave flex and a fabricated compass.

If Allen wants to have a 180 degree turn, he is better off using O-84 for the outside track if he has the room.  His comment on using O-60 might indicate he does not have the room.

The way his question is worded, I agree with boilermaker1 that he is looking at a 90 degree turn.  The outside track’s straight section into the curve would need to be 6” longer then the inside track’s straight section.  I am not home so I can’t provide a diagram, but Dave’s drawing shows this by the staggered straight sections going into the curve.

@DoubleDAZ posted:

You can’t connect an O-72 switch or any other regular track to the ends of the O-72 Wye unless you first add one of the fitter pieces that come with the Wye or trim the inside roadbed on the switch or track you want to attach. The roadbeds will interfere with each other without the fitter pieces or trimming. Trimming an O-72 switch reduces its resale value, but I don’t believe it interferes with its operation.

Dave, I can confirm that if one did want to trim off the excess from an O-72 FasTrack switch, it would not interfere with any of the switches electronics or mechanical operation.  Here's a pic of one with the bottom cover removed showing the internals.

And like you I wouldn't recommend it.  They also come with 3 fitter (1-3/8" isolation) pieces, so there's no extra cost in using them, other that the extra space they occupy.

Double DAZ Dave,

Thank you for providing me with the diagram of how to do a Double Main Line. Can you Please do me a small favor? Could you go to your Railroad Software to show me how to make a Double Main using a 072 Wye Switch maybe two of them to connect to the Double Main Line?

If you need additional information my phone number is (314) 537-4733

Thank you for your help and time

I really Appreciate it very much

Sincerely

Allan Martinez

Hi Allan. Not exactly sure what the end goal is or why O-72 Wyes, but here's some examples that might help. I assume you haven't installed SCARM, so I didn't include the SCARM file.

Curves in the Blue ovals are all O-72. Curves in the Green ovals are O-60 inner and O-72 outer. I added the Yellow example in case that is kind of what you're after trying to use 2 O-72 Wyes. The center-to-center tracks clearance is around 6", you can see the filler pieces I added to increase the default clearance. Also, don't forget that the small fitters attached to the Wyes are the 1 3/8" ones with the half roadbed.

Maybe someone should show him a double crossover?  I know Lionel doesn't make one, but I'm suspecting that's the direction he's headed in.  He could make one with 2 left switches, 2 right switches and a crossing track.  Just a thought.

Don’t assume that because of the way I did the examples, but if that’s the goal, RH/LH switches would be the preferred method.

Truthfully, after using curved switches for crossovers, I much prefer the Ross switches with the straight diverging path, much less waggle going through the crossover.

@DoubleDAZ posted:

Don’t assume that because of the way I did the examples, but if that’s the goal, RH/LH switches would be the preferred method.

Those were very nice examples btw.

Dave and A.Wells, I was also wondering along those lines.  @Alan Mancus Is maybe something like one of these what you have in mind?

SCARM Files attached.  Parts List available upon request.

Thanks, A. Wells, kind of you to say.

Steve, I should have added the Blue one, I’ve used that before. I didn’t think if it because of his first question about adding the O-72 switch. Thanks for posting it.

Mike CT,

Thank you for the tip on using a fabricated compass and Gargrave Flex Track. I have a question about your idea Drilling the holes at different radius points I can understand, but placing the point for the start of the compass I don't understand.

I must have been home sick in bed when the Math Teacher was Talking about Measurements for drawing radius and circles. If you can find the time could you explain a little about where to place the point of the compass to draw where the Arc of the Radius would go Please.

Thank you for your time

Sincerely

Allan