How does one determen the radious when laying track.? And how do you do it freehand.
The radius is to the center of the track (between the rails).
There are two easy ways to do it. One is to get a yardstick. Drill a 1/8 hole at the 1 inch mark and then holes at the 19, 20, 21, 22, etc inch marks. Put a nail in the yard stick at the 1 in hole and put a pencil in the hole for the radius you want (remember that the radius will be 1 inch less than the mark (the hole at the 19 in mark draws a 18 in radius.) Swing the yardstick around to draw the radius.
I have been model railroading for 30 years and have been using the same yardstick for the last 15 years.
Another way to do it it to take heavy carboard or masonite and repeat the above process drawing arcs every 2 inches. Start at 18 in and then go even increments, then draw another series at 19 in and draw arcs in 2 in increments. Cut out the arcs carefully and smoothly. You can then lay the arcs down on the roadbed and trace whatever radius you need. If you are in HO, having the arcs 2 in wide means that once you establi***he one radius you can automatically draw the radius of the adjoining track around a curve.
Dave H.
the way i did my radious is messured out 22" 24"and 28" solid copper wire.then i wrapped one end around a sharpy (black marker). put the marker about center on the last straight section and snugged up the wire and tacked the other end to the table. then from there just moved the marker keeping the wire tight and made a half circle.
then when i laid the flex track i kept the line in the center of the ties.
as for determining the radius i just went as large of a radius i could go in the space i had.
Christmas is over, but you better watch out (as the song goes). Unless you are running very small locomotives and rolling stock (pre WWI), spacing ajoining curves only 2 inches apart is going to invite disaster. You will have interference on the curves when two trains pass each other. Your minimum spacing at these radii should be 2 -1/4", 2- 1/2" would be even better
I just set up ajoining tracks of Bachman’s E-Z Track at 33 1/4 and 35 -1/2’ and passed two Branchline 85’ pullmans next to one another with only an 1/8" clearance. Need I say more?
Don’t forget about easements. Basically it’s the same as above but allow a couple inches to unwind outside the circle. An easment virtually starts out with radius of infinity and approches the turn radious at some point in the turn. It’s a smooth transition from straight track to curved track. In reality going from straight track to curved track causes quite a jerk.
You might not be able to see the jerk, but the guys in your train will. You will too when you see it derail in some circumstances.
Years ago I bought a box set of everything you would need to lay out track from Arbour Models. It was called Gandydancer and all the pieces are 2" wide for ease of laying double track. I don’t know if it is still available. The yardstick is an excellent idea. Just remember to put the radius you want on the track centerline and the 1" hole in the center of your arc and as level as you want it to be. Good luck, have fun and enjoy.
Archie
Please keep in mind that the dimensions used might be different in other scales. For example, you’d get some really broad curves, great for streamlined passenger equipment, using a curve of 20 inches or greater radius!