Large Scale Central

Switch Control.....rod system

General Discussion
#1

I’m slowly working on a project developing a rod system to control a remote switch, about 25 feet away from a control point. It is too long a distance for a choke cable application, due to friction over such a length.

The one bonus is that it is a straight run for the rod.

This type of system was at one time used extensively by the real railroads, to control switches, and signals, from control towers, or other places, especially in major terminals.

One feature that I remember a drawings of, was a “Compensator” to adjust for temperature fluctuations.

Any information about the use of this system, would be greatly appreciated.

I use choke cables extensively, and usually don’t need remote controls for most situations, because we walk along with our equipment, when operating. There just happens to be this one location that could be easier to access using a remote system.

I don’t want to run wires, or introduce an electrical system, which would be more trouble than a simple mechanical rod system.

Besides…it might be fun…!!

Fred Mills

#2

Instead of a compensator, how about just building a bit of overthrow, and using springs to take up the difference.

#3

…good thought…thanks…

#4

Knowing a bit of your operations, the following info would help. Is this a single straight line of sight distance? Does it run along one of the standard 2 x ? road bed planks?

If the answer to both is yes, the I would suggest the cheapest method would be to use standard 1/8 inch (or metric equivalent) welding rod for either TIG or gas welding. They come in 3 foot or maybe meter lengths. They can be threaded on each end and small rod couplers (I can’t remember the exact name off my head) to join sections. The can be routed through small screw eyes screwed directly into the road bed. Your conventional ‘L’ bracket for the throw and a design of your choice harp style switch stand at the other end.

#5

Many folks use brazing rod, its a brass alloy and can be threaded too.

#6

Have you given any thought to using a pneumatic system?

#7

Steve;

I have been quite aware of the air systems, but I also have checked out the overall costs.

If I needed extensive remote controls, then looking at electrical or pneumatic, would make great sense.

The choke cables serve well, when all we need is something to prevent bending over, but they have about a 5-10 foot limit. They are quite inexpensive, and require very little maintenance if properly installed.

Both of those systems require extensive runs of wire, and or tubing, plus an air supply, or electrical power supply.

We operate our trains, as we walk around with them, throwing switches as necessary, manually.

This one switch is at the end of a long narrow path, which I am trying to prevent operators from using. The switch gets limited use, as it is at one end of a passing track…some people might be inclined to suggest using a spring switch, but I would rather not.

The rod system should work well, if properly installed, and will not need an air supply, tubing, valves, etc., and the costs of maintaining such a system.

Thank you for the suggestion.

Fred Mills

#8

So you will need a straight shot, a stiff rod (shut up rooster), and some loops for the rod to slide through to keep it from deflecting.

I’d agree to have springs at the “business end” to handle overtravel, which you will want since the operator can only go by feel, or latching the operating lever in one of 2 positions.

I’d also put a mechanical, over scale target to verify the movement at the switch itself.

Greg

#9

What, is the path too narrow, or just unsafe?

I really like Greg’s suggestion of an oversized target to display the switch position. That way the operators can see if the thing moved, and if its set the way they want it.

Since British railroads used similar systems over some distance, sometimes a quarter mile or more, I would think you could make it work in scale. When you do, please show us how you did it. It may help some of us, like Devon, with oddly placed diversions…um…switches.

#10

Lots of great suggestions…Thanks everyone…they are all appreciated.

To answer a few questions. Yes the “pathway” has become a wee bit narrow due to the extension of the original roadbed, in order to accommodate the passing track. Yes, I am planning on an indicator to show that the switch is actually in one position, or the other. Yes, using eyelets is the way I think I am going, as a means to support the “Rodding”.

At this point, I have a hundred feet of galvanized chain link fence, bottom wire (11Ga) which seems to be tempered enough to do the trick, all in one run. It was rather inexpensive, at $9.50 or so, Canadian. The eyelets were only $1.89, per packet of ten.

I will be using my regular 2 inch, flat angle brackets as bell cranks, after drilling for the fulcrum hole, and appropriate holes for the rodding.

I was looking at an old Aristo switch throw, with the lantern on top, as a base for an indicator. I would remove the springs, and attach it to the throw bar, of the switch, replacing the lantern with a painted “Board”.

The main track, and passing siding, are both on a grade of about 2%, or slightly more, so the “Up bound” trains would be directed to the main line, while down grade they would use the siding, if a meet is planned at this location. This us up to the dispatcher.

Fred Mills

#11

So, just where is this switch on your RR? So far, I just can’t figure it out.

#12

I have a switch that is difficult to get to under a low tree 7-8’ away from my path.

I used plastic flexible pipe 1/4 I think it was, that I found at home depot. I greased up the inside best I could with real automotive grease then ran a 16 gauge wire through it. To keep this pipe from moving when actuated I drilled a hole through several PT ballusters and drove those into the ground. The pipe was then put through the holes to the switch. The switch itself has small stakes driven between the ties to prevent it from moving when the wire is pulled or pushed. At the switch end I bent the wire to fit into the slot where a switch machine would go. At the operating end the wire is bent into “T” shape.

Simple.

It doesn’t take much to move the points. 4 years on the RR now and it still is working well.

#13

Dave M. - To answer the recommendation for steel rod, either will do well in the tension direction for what Fred wishes to do, however the steel will be a better bet for the compression direction. It will take less support of the steel with the eye screws. It is also the reason I recommended the larger diameter material. Twenty five feet is a fair distance to ‘push’ a rod with out significant deflection. Time will tell whether Fred’s solution will work or not.

Good luck Fred. Sounds like you are off to a great start.

Bob C.

#14

Bruce, and anyone else familiar with the IPP&W Railroad.

You can probably find this “Passing track” somewhere on our web page; www.ovgrs.org/

The location would be listed as “Watkins Siding”. The location is downgrade, or East of Bell; along the fence, towards the trackage under St.Helens.

I don’t do pictures, but many pictures have been taken and shown on this web page, and in blogs, by a great number of good photographers.

When I get this project done, even if it is a failure, I will have some pictures taken, and someone will post them here. I’m sure.

I may start working on it this week, as the weather is looking rather good.

Fred Mills

#15

Fred, if you used an offset spring from throwbar to sleeper, that will keep the points thrown one way or the other, your choice. then you could use a pull chain or string of some sort to move the points in the other direction for the duration of the time needed. This would be used only if you can’t make the rod system work. Feed the string or chain through conduit to keep it out of the mud.

Just thinking outside of the box.

#16

Steve;

Stabilizing the actual switch is no problem, as all the track and switches are mounted on 2x PT lumber. About 3/4 of the whole railroad is raised off the ground, so “Mud” is not a problem either.

All track is nailed to the roadbed. We use small flat head nails. The nails are used through small holes drilled through the ends of the ties…this prevents the ties from ever being compressed in the centre. The nails rust, and are hardly noticeable. We try not to drive the nails in too far, so that they are easily drawn out, if need be.

I do appreciate your thoughts…

Fred Mills

#17

Fred

No pictures after the changes but this is what it looked like before. The bridge by the gate has been removed and the siding extended another 8 feet.

#18

This is the turnout were the rod would need to run to. It also shows how narrow the walkway is at this point, with the extension it is even more difficult to reach as Fred has indicated.

#19

Close up of the switch control arm.

#20

Hi Fred,

You probably are already aware of Dubro, but in case not, they make an array of control-rod products (for R/C planes) and related hardware what might be of use. For example, bell cranks, bushings, ball joints & etc.

http://shop.dubro.com/c/aircraft_bellcranks

Cliff