I want to model the rod and crank mechanisms that were once used to switch turnouts from a control tower. Are these parts available in N scale from any manufacturers? The crank arms are a flat L-shape and the rods end in a U-shape fitting.
My idea is to build a slow motion motor using an air cylinder or a slow-motion switch machine located some distance from the turnout.
This web site shows one possible arrangement. www.members.fortunecity.com/ozz_scott/radcrank.html
I know exactly what you’re talking about, since I need the same things in HOj. Unfortunately, I don’t know of any source. I expect to make masters of the two different types I want, as well as the little roller stands that support the rods, then use them to mold the required parts.
You might want to reconsider trying to use the prototypical rodding above the ties to power your points. Even in HOj (1:80, twice-N) scale, the rods are pretty flimsy. I, personally, am torn between having the point throw rods impart motion to the interlocking and just leaving it fixed, for cosmetic effect. As for the points themselves, a nice, beefy 2-coil machine under the roadbed is my motion-imparter of choice. (I don’t have anything against the Tortoise - but I already own a big box of twin-coils.)
One advantage with immobile, cosmetic effect only, rodding is that you can simply glue everything in place with CA. No need to assemble things with microscopic clevis pins…
Chuck (modeling Central Japan in September, 1964 - with mechanical interlocking)
Are you thinking that the rods push? I was considering a pull action and some kind of piano wire should work no matter how long. One has to consider the force on the crank arm and not pull it out of its mounting.
How do you make a master and what do you use for casting materials?
Hello “Nick,”
You might want to see the article below on the subject of mechanical interlocking linkage:
Model mechanical interlockings
Model Railroader, January 2004 page 122
trackside rods that connect turnouts to the tower
( “DARNABY, BILL”, INTERLOCKING, HO, MR )
Bill’s linkage is HO scale and non-working, but I think you’ll find some useful background and modeling information. The actual pipe used for rodding is 1"i.d., equivalent to about .008" wire in N scale. I’d never say that making a working, scale-size linkage is impossible, but it’ll be quite a challenge!
Good luck,
Andy
I make my own bell cranks using 1/4 inch X 1/16 inch brass strips. I solder them together to make an L. I drill a few holes in each end to make the throw adjustable. I bend a large Z in the push rod to act like a spring that can be put under pressure or tension. It takes some of the pressure off the turnout but keeps enough for the turnout to stay in position. You need to experiment a little.
I use 1/2 inch long brass tube with large enough ID for the push rod and put each piece in a suitable cotter pin. I drill holes under the layout to push the ends of the cotter pins into. This makes a guide for the push rod. My throws are all manual from the facia.
rich
Are you looking to provide a real working linkage or to model a cosmetic system representing the connections found on the ground between a tower with an Armstrong frame and the gear on the track?
If the former and you are placing the gear below the baseboard you don’t need the cranks to be L shaped unless you want to go to the effort for your own satisfaction. You can achieve the same end by using squares of suitable material. The important thing is to be careful about drilling the holes correctly. The hole for the pivot in one corner and the other two holes in adjacent corners. This isn’t stylish but it works.
If you want the latter (cosmetic) and can accept a bit of scale variation you might like to look at some of the detail bits available for UK model railways.
I would not try to mix an attempt at modelled appearance and working equipment. You will never get materials strong enough to do the job in the necessary size (unless you can tap into NASA’s budget and material supplies).
It is possible to use micro-filament thread to operate semaphore signals… but the usual practice is to make the (apparent) modelled cable run from the signal box (tower) to the signal cosmetic while the micro-filament only runs from the signal arm to a linkage below the baseboard. Whatever is below the baseboard (either a motor or a further manual drive) is more robust to take the wear and tear.
Where appropriate adding the point rodding and/or signal cable runs really makes a model look good.
As far as I am aware the usual practice in the USA was to use pipe/round rodding carried on (or between) rollers with a U shaped slot. The UK practice was and is to use square channel sitting on rollers. (This might make UK bits innappropriate).
The rollers are only between 1" and 2" diameter - about 1/2mm in H0 so they wouldn’t exactly stand out… the thing to focus on would be the frame that carries them. Again