I have a double track main line and I want to cross over one of the lines using a number 8 switch and a crossover . Does any one know what angle the crossover would be? I hope I’m explaing this right.[:)]
The ‘number’ of the turnout indicates the frog angle, in terms of units. So a #8 means that for every 8 units travelled away from the frog, the diverging route will be 1 unit away from the straight route. So 8 inches away, the diverging route will be 1 inch away.
The rest is from Trigonometry class. Knowing the length of the side opposite the angle as well as the length of the side adjacent to the angle, you need the arctangent function. Since the opposite sie is 1 unit, and the adjacent side is 8 units, you have arctan(1/8) which is approximately 7.1 degrees. Makes no difference on how far out you go, the ratio of diverging side to straight side will always be 1:8. Likewise you can use the same calculation to find the angle of a #6 ( arctan(1/6) = 9.5 degrees, 1:6) and a #4 (arctan(1/4) = 14 degrees, 1:4).
Moreso than the actual angle though, for a crossover you are probably more interested in how far apart the parallel tracks will be when you put two such turnouts together to form a crossover. This depends as much on the brand as the angle - some brands have more track on the diverging route than others. The angle is the same. You can usually cut the rails back if the stock lengths cause your tracks to be too far apart, or add short filler sections if they end up too close.
–Randy
If I understand your question correctly, you want to use one number 8 turnout and one crossover the make a branch off of one mainline cross over the other mainline. For this you will need the smallest degree crossover made, and even that may not be the proper angle. Depending on the brand of crossover you use, you might be able to find one that is 14 degree, but most are 19 or 24 degree. Even 14 degree might be too acute an angle for what you want to achieve.
Thanks for both answers. Randy you must be a math major!
Carcole is correct I want to use one #8 turnout and one crossover. I just check my Walthers catalog and Atlas lists a 12.5 degree crossover so I’ll give that a try. That is if I can find one. My Local Hobby Shop has been good in finding stuff for me so I’ll give him another challenge.
When you get down to that size of a crossover, Atlas is not a good choice in my opinion because so much of the rail will be covered with plastic insulation that your locomotives may stall going through it. Check Peco crossovers, they are made much better than Atlas.
Electrical engineer, close enough [:D]
Just a note, you’re looking for a crossing. ‘crossover’ generally refers to an arrangment with 2 or 4 switches to ‘cross over’ from one track to another. I don’t know that anyone makes one to match a #8. Be careful using a 12.5 degree, that the track from the end of the #8 to the crossing doesn’t end up with a kink or a curve of such radius that it renders the use of the #8 pointless.
–Randy
At this point, if the premade cross over doesn’t line up with the #8 turnout, I would consider hand laying the crossover. Once you get the hang of it, it’s not too bad. It takes time but you can get an infinite number of frog angles.
I checked Walther’s 2004 Catalogue last night and found the angle on their #8 turnout listed at 7.9 degrees meaning you would need a 15.8 degree angle cross track. This information does not refute Randy’s calculations but it just points out that there can be significant variations between different manufacturers. Just as a 2.4 liter automobile engine can have a displacement ranging from 2345 cc’s to 2444 cc’s, a nominal #8 turnout can have an actual frog # ranging from 7.50 to 8.4.
Marc’s suggestion is probably the most viable, unless you want to start with a premade crossover and handlay the switches. Another solution is to use two single crossovers (a left and right hand) which can be located either adjacent to one another or at different locations (e.g. separated as far apart as possible). The advantage of the separated crossovers is that you can swap tracks two trains at a time instead having to move only one train at a time.
Another option is a Peco single-slip switch. This would let you not only cross over from one track to the other, but enter the branch line from either mainline. A Peco slip switch tracks cross at 12 degrees, which is the same angle as their turnouts, so a Peco large turnout and Peco single-slip switch should match up perfectly. A double-slip would give you the additional option of using these turnouts to cross over from one mainline to the other, in addition to being able to enter the branch line from either main. You can see pictures of Peco turnouts, crossovers, etc. at http://www.cchobbies.com
Cherry Creek Hobbies in Torrington, Wyoming, is one of the best dealers in the U.S. for Peco track products.