I know that attempting to make a double crossover with Atlas Snap Switches is a worthless endeavor. It will just not work. However, what about doing a single crossover with two Atlas Snap Switches. What should one be aware of in attempting to do this? I would appreciate all input from the experts. Thank you ahead of time.
One of the problems with crossovers of any type is that you create an S-curve, with your trains first curving right, then left, (or the other way around) rather quickly. This puts longer engines and rolling stock into a bind. The couplers on one car don’t line up with the couplers on the next car, and derailments are frequent.
The tighter the turnouts, the worse the problem. Unfortunately, Atlas snap-switches are about the tightest your’re going to find, about a #4.5 turnout. Even worse, the diverging paths are curved all the way, unlike, for example, a Walthers #5 turnout which would be a much smoother transition and would fit in almost as tight a space.
If you are a transition era modeler and you only run 4-axle diesels and 40-foot boxcars, you’ll probably be OK. Otherwise, consider alternatives. Your trains will thank you.
Atlas Snap-Switches are even tighter than that, about a #3.3 frog. Atlas “#4s” are actually about a #4½.
To the Original Poster, Snap-Switches would make a very sharp crossover and might only work when pulling with shorter cars and locos. When shoving with longer or mixed-length equipment (as in switching), it won’t be very reliable. Personally, I’d use #6 for standard crossovers made with Atlas parts at least.
As Mr. B noted, because of the curved diverging leg of the Snap-Switch, a crossover made of “straight” Atlas turnouts (“#4” or #6) might not take up any additional room.
One can also use an angled crossover if the track can curve a bit, which eliminates s-curves even with lower-numbered turnouts.
Not true! I built a double crossover using Atlas turnouts. It appears that Blogger is down but when it is working check out my blog.
http://melvineperry.blogspot.com/2012/06/june-25-2012-my-double-crossover.html
This is a picture of my Atlas double crossover, 2" center to center.
They are Atlas #6 Custom Line turnouts with a Atlas 19° crossing. My longest cars and even a Bowser Big Boy do not derail.
Mel
Nice work, but the Original Poster is asking about Snap-Switches, not #6s.
Mel is correct. I used two Atlas number 4 snap switches for a cross over in two separate areas. Ran everything I owned though them up to back to back SD 60s and 60 ft freight and 72 ft passenger cars. Never had any issues forward or backward.
The 40ft / 4 axle limit for 18 inch radius and number 4 switches is a myth. Modern stuff is designed to run on it.
Sorry, to me all Atlas turnouts are snap switches. [:D] But seriously the Atlas turnouts work great as double crossovers. The only derails I’ve had were due to improper wheel spacing. The quick S will find all kinds of problems that you didn’t know you had but when everything is to proper tolerance NO DERAILS through my kitbashed double crossover. Long light weight cars wobble badly but stay on the track at full throttle.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
My Model Railroad
http://melvineperry.blogspot.com/
That imprecision doesn’t help inexperienced builders, unfortunately.
Snap-Switches are a specific product with a very sharp frog built into an 18" or 22" (now) radius curve on the diverging leg.
Atlas calls the #6s “Custom-Line Turnouts” – not “Snap-Switches”
Since they are #6s, I’m not surprised.
Atlas Snap Switches have a curved diverging track so it can be better incorporated into a curve…helpful in a lot of small layouts. I use one to create a spur out from a reversing loop. And they are not labeled as having a particular frog #. But using the curved diverging tracks as part of a crossover would be a problem, IMO.
Better to use #4 turnouts or #6 turnouts since the diverging rails are mostly straight beyond the frog.