Double Crossover with Shinohara #8s

[stilson4283]

The RIT MRC is building a module layout and we are looking to use Shinohara #8s on the mainline. Now to help conserve space I wanted to do a double crossover with the #8s but I don’t know what the crossings degree would be. Can anyone help me out?

Chris

[jack S.]

Chris, How about taking a protractor to the train shop and laying it over a Shinny #8 ? However I think you're gonna be disappointed - I have no knowledge of a commercial crossing at the low angle you'll need, but good luck just the same. If you find one, let everyone know.

Best switches,

[snowplough]

According to Central Valley's website (www.cvmw.com/cvtswitch/index.htm), the frog angel of *their* no. 8's is 7.125 degrees.


snowplough

[Throttle_JCKY]

I imagine you will have to custom build your diamond, not hard to do actually!

#8's have such a low angle.

[Tom Curtin]

Well, I dusted off my engineering math and determined the following:

using the "official" formula that the frog number of a turnout = 1/2 the cotangent of 1/2 the frog angle, it works out that the frog angle of a #8 turnout in 7.1527 deg.

Now, I thought about this, and I believe that if you're putting in a scissors crossover, the angle of the diamond would work out to be double the frog angle of the turnouts being used (makes sense?); therefore 14.305 degrees. This is very close to 15 degrees, and while I haven't looked to see what's available on the market, 15 degrees sounds to me like it might just be one of those that's made commercially.

Now, of course there are a couple of obvious assumptions here:
1. Shinohara's #8 frog angle may or may not be precisely 7.1527 deg.

2. My statement above, that "14.305 degrees is very close to 15 degrees" doesn't necessarily mean that it's close enough too work well for you.