Cross Over on a Curve

I need one too. I was going to use 027 30 degree crossing and cut it down. I have a double track main where I need one track to cross another and of course its right at a curve.

There must be some smart person out there that can help J Daddy and me.

 

Paul Edgar

Ross Custom Switches has been known to make custom tracks.

Contacts

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tom@rossswitches.com

technical help:
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A crossing on a curve without a little bit of straight might be a problem without very precise cutting and guard rail placement. That said, The Ross 11-degree crossing gives the closest fit between the curves. Here's one with a 22.5-degree crossing.

 

 

Here's the one with the 11-degree. Note that Gargraves O-72 curves are 45-degree arcs, while the Ross sections I used here are 22.5 degrees.

 

 

Cutting 11-degrees of one of the curves an putting it on the other gives you parallel lines with a cross in the corner.

Are both crossovers on a curve or is it a straight that bisects the curve?  If it's the latter I don't see any problem with making one.

Not to be a picker of nits, but just to avoid confusion on terminology.

 

This is a crossover:

 

 

 

 

This is a crossing:

 

 

Jim

My initial reaction was going to be something like needing an O72/O54 curve turnout on the outer loop and then an O72/O84 (or 96 maybe) turnout on the inner loop and then you could try to get them to line up.

 

Then I went in to RR Track and saw there was not a standard Ross curve turnout for O72 and something larger than O72.

 

I made a quick attempt to do something using a wye for the inner loop, but to get the plan to work out, the loops would have to be very far separated on one side and very close together on the other side (by side I'm using loose terminology meaning ~ 90 degrees of the circle).

 

This used mostly stock pieces, I cut a custom 11.25 degree curve to help line up the geometry and there is a small straight piece inserted in between 2 of the outer curves to separate the loops a little  (probably should have been a bit longer)

 

Maybe this will help someone else get their gears spinning for a better solution.  Almost forgot  - the dual curve turnout is the O72/O54 mentioned previously.

 

 

 

-Dave

Thanks for straightening me out Jim.  I do take meds for that.  BTW I've been married to a lovely nit picker for 48 yrs so I'm used to it.

Nick,

 

It's really only important in certain circumstances. I know of a guy who called a hobby shop and asked for the price on a crossover when he meant a crossing. Had to pick himself off the floor!

 

Jim

Here's some more attempts.  got the track closer together, but there are starting to be quite a few straights where you might no longer consider this a loop.

 

I have an error with the custom piece I mention in the previous post.  I made an incorrect assumption on the number of degrees in the O72/O54 turnout.  The below ideas do not have that error, so as a result some odd-ball curves were custom cut to balance out the odd # of degrees in the turnout.  (I didn't notice before because I did not end the curves with straight sections, so I didn't note the angle was off quite a bit.  Note the below has at least one straight off of each ending curve so you can see we are dealing with roughly 90 degrees worth of circle for what is shown)

 

For all, there is a 7 degree O72 in the cross over area and an 18.4 degree O72 in the outer loop.  The differences between the three examples beyond that is mostly the number of stock curves depending on which position the wye is in.  For the first two examples, the custom cut piece is right after the turnout so that any straights used are in the 45 degree position into the circle.

 

For the far right example, it was necessary to put significant length straights in the outer loop right after the turnout (even before the custom curve) so the tracks didn't hit each other.

 

Of course, note the scale here is 1 foot per box.  We are getting to the point where the 1/4 circle is taking up over 6 feet as opposed to ~ 3 feet for a standard circle.  Not sure how much space you might have, but this can get big fast.

 

 

 

-Dave

To do a crossover on a curve you need two CURVED SWITCHES. A curved switch is one that is curved on BOTH routes. I had two on an HO layout I built many years ago and they worked flawlessly.

 

The examples posted above create some nasty reverse curves that would be a problem for some equipment.

That was my first thought too(and maybe the pic is not clear enough, but the outer switch in all of the above is an O72/O54 curved switch).  But I didn't see a standard double curved turnout that had something greater than O72 combined with O72 (which is what you would need for a double curved turnout to get out of the inner loop if it's O72).  That's the only reason I started messing around with the Wye.

 

Now that I'm thinking more, the wye could be replaced with some modifications if you used a RH O72, the straight would take you to the outer loop.  Eliminating the wye seems to make it much better!  (I think this eliminates most of what would be considered the most problematic elements of the previous examples)  Also helped greatly with the spacing.

 

Obviously there is still the issue of having 38 degrees worth of an O54 curve here, so if any equipment really needs no less than O72, that could be a problem.  No way around that though to get between the 2 O72 loops.

 

 

I agree you would definitely need to try this out "dry" before constructing it on a layout permanently.  The paths in the previous examples are certainly not something you would want to take at high speed.

 

-Dave

 

VERY tough to do with sectional track.

OK my bad.  I am talking about a crossing, no turn outs involved.  It   My situation is a straight track which I want to cross a 072 curve.  Is it going to be a problem just to add a crossing in the curve?  It seems to me that the curve might not accept them straight  track.

 

Thanks for the replies.

 

Paul Edgar

 

 

OK Paul, that's what I thought you wanted.  It's not that hard to make with one section of of GG 072 and one straight.  If I had the time I'd make one for you but my plate is full until Thanksgiving....moving into our retirement home that I've been remodeling since early spring.

You might need to use the ScaleTrax crossings and curves from MTH.

 

Andrew

 

That would be the better way to go.  BTW I think Paul is using Gar Graves track.

Jim, thanks a bunch for "picking that nit".  My website may have 5 pages that need to be corrected and I'm really trying for accuracy.