If its a no.4s turnout, and it needs 4 units of length to spread one unit, can someone tell me what a unit is in model train vocabulary. I read units in measurement, and confusing, What is a unit in turnout world?
Thank you all in advance, and still a model train lover.
The units are the same in the prototype and the model. For example, a #4 turnout moves to the side 1 unit for every 4 units - You can measure in inches, scale feet, etc.
Be aware, that if you are using an Atlas Customline #4, it is actually a #4.5 turnout. If you are using a ‘Snap-Switch’, it has a continuous curve(either 18" or 22" radius) through the turnout. That ‘spread’ is not from the tip of the points, so do not get confused there. Just draw a like 4" long, and another line 1" long at a right angle to the first. Connect the them to form a triangle. Lay your #4 turnout on the triangle, the centerline of the turnout legs should drop right onto the triangle.
Jim
Jim has given an excellent response. You can think of the number as another measure of the frog angle. The picture below show a jig for forming a no 6 turnout frog. The angle is formed by measuring along one side by 6 inches and then over 1 inch to form the other leg of the angle. Credit to Charlie Comstock for the jig design.
Jim
Since it’s a ratio of two numbers, the units cancel out and you’re left with a unitless number. So it doesn’t matter if you’re measuring in nanometers, miles, or lightyears. The angle is the same.
Steve S
So if I understand this the length of the angle is what make up the turnout number, example no.5 the angle is 5 inches,if i have this correct. What determines where you place a turnout,or can you place a turnout ( anywhere ). Is their a maximum of the amount of cars that can go into a turnout?
Thanks for all your Help!!!
All suggestions were helpful.
Angles are measured in degrees. A #5 turnout means that the track diverges 1 unit (inches, centimeters, whatever) for every 5 units of length. (that’s about 11.5 degrees.)
Steve S
There is no limit to the number of cars going thru a turnout.
Cars parked on an industrial spur or passing siding must be far enough in that a passing train doesn’t make contact while going by.
Dave
No, not angle. Ratio. The ratio comprises the number of units left or right of the through route, measured at the frog point, for a given number of units of length down the through route from the frog point. If none of that makes sense, perhaps it is terminology that is tripping you up.
http://bellsandwhistles.us/modelrailroading/Clinic08_handout.pdf
The higher the number of the turnout, the less divergence it has because the turnout goes further down the track for the same amount of divergence as a turnout with a lower number. The ratio is run/divergence, so a #6 turnout takes the rolling stock further past the frog to get the same unit of divergence as a #4 turnout. It has nothing to do with angle…the name of the turnout, I mean.
Placement of a turnout? Where it will do for you what you need it to do! It affords access to trackage off the main route. Why do you need it? How close must you get to where you need it, and how many cars must you be able to park past the turnout in such a way that the parked rolling stock doesn’t foul oncoming rolling stock or locomotives? IOW, figure out beforehand why you need a turnout, and where it will do you the most good. If you intend to switch 60 cars beyond the turnout, place the turnout where you can park 60 cars beyond it safely.
How long is your rolling stock? Forty feet, sixty feet, 85 feet (passenger cars)?&n
Think triangle. Find a place where the insides of the running rails that taper into the frog are one unit apart (the unit can be any unit of length that’s convenient, millimeter, fraction or decimal inch, full inch, foot, cubit, yard - anything beyond a yard would probably enter a curve, even if you’re building in Brunel gage, 7 feet 0.25 inch between railheads) then measure back to the point of the frog. The number of units you measure is the frog number.
The turnout is simply a distorted curve. If your rolling stock can take really tight curves you can use low frog numbers. Anything that will round 24 inch radius will be happy with #5 in HO (my personal standard.) Stiff locomotives, full-length Pullmans and 89 foot humonguboxes and piggyback flats need #6 turnouts (and 30+ inch radius curves.)
The best way to test out your tracking is to take a bunch of full-size turnout templates, flop them onto a drawing of your proposed track plan with a layer of foam insulation under it and bend flex track to match any route you think might be, “Iffy.” Connect up test leads and run locos and cars through those routes and see what actually works, and (more importantly) what doesn’t. I discovered certain mis-matches between car lengths that I have to avoid - my Japanese auto racks and container flats don’t play nice with fifteen ton four-wheelers on my minimum radius, so I have to keep an intermediate-length car between.
Chuck (Modeling Central Japan in September, 1964)