Equipment to connect points/signals to a signal box and a level crossing query!

[Richie Kynaston]

Evening all,

Hope I am posting this in the right place.  Can anyone give me any dimensions for the cranks used within point rodding, and the height/width of the point rodding 'U' channel please?  Also, the wheels that wire/chain goes around to redirect the wires for semaphore signals?  I know this is probably far from a simple question, but I have seen reference to what I would term double cranks being used to allow adjustment in long point rodding runs, is there any fixed rules surrounding when and how these are used?

 

One final query, if I may.  In a manual box, the wooden level crossing gates generally turn through 45 degrees, when moved from the railway 'closed' position to the road 'closed' position.  I know the operating wheel in the box (from the ones I have seen) controls a cog which moves a straight ratch up and down, but can anyone tell me how that translates into circular movement for the gates please?  I have searched over Christmas on Google but not come up with any operating details, pictures or diagrams and am somewhat baffled, I assume it has to be rods or bars between the box and the gates as I don't think wire would be suitable.

 

Cheers

Richard

[phil-b259]

Evening all,

Hope I am posting this in the right place. Can anyone give me any dimensions for the cranks used within point rodding, and the height/width of the point rodding 'U' channel please? Also, the wheels that wire/chain goes around to redirect the wires for semaphore signals? I know this is probably far from a simple question, but I have seen reference to what I would term double cranks being used to allow adjustment in long point rodding runs, is there any fixed rules surrounding when and how these are used?

 

One final query, if I may. In a manual box, the wooden level crossing gates generally turn through 45 degrees, when moved from the railway 'closed' position to the road 'closed' position. I know the operating wheel in the box (from the ones I have seen) controls a cog which moves a straight ratch up and down, but can anyone tell me how that translates into circular movement for the gates please? I have searched over Christmas on Google but not come up with any operating details, pictures or diagrams and am somewhat baffled, I assume it has to be rods or bars between the box and the gates as I don't think wire would be suitable.

 

Cheers

Richard

 

The “double cranks” seen in point roding are called ‘compensators’ and compensate for temperature changes causing the rods to expand or contract. They are required for all roding other than the very shortest of runs.

 

The compensator works by changing the direction of the rod so a ‘pull’ on one side becomes a ‘push’ on the other. Their placement is done by calculating the forces on each side so that they are balanced and a increase in roding length on one side is ‘compensated’ for in the other.

 

It should be noted that despite appearances the compensator is not always the middle of the ridding run.

 

This document is worth a read http://www.irse.org/minorrailways/publicdocuments/PA01%20-%20Mechanically%20Operated%20Points%20v2.pdf

Edited January 3, 2019 by phil-b259

[RailWest]

One final query, if I may.  In a manual box, the wooden level crossing gates generally turn through 45 degrees, when moved from the railway 'closed' position to the road 'closed' position.  I know the operating wheel in the box (from the ones I have seen) controls a cog which moves a straight ratch up and down, but can anyone tell me how that translates into circular movement for the gates please?........

 

Like so many things "it varies" :-)

 

1. If the road crosses the railway at right-angles then the gates would move thru' 90 degrees, not 45. That angle would vary of course if the road made an acute crossing.

 

2. Not every crossing had 4 gates, nor were they all worked by wheel - many were done by hand 'on the ground'.

 

3. There were many different types of 'gate wheel' and drive mechanism, it varied depending upon the original railway company and/or their signalling contractor.

 

4. In simple terms the drive from the wheel was a rod (similar to point rodding, but often thicker) which drove a series of cranks connected by other rods to cranks attached to the bottom of the gate pivots. Much of this would be hidden out of side under covers in the road surface. There are some generic schematics in various books on signalling matters.

 

5. In some places with 4 gates the gates over-lapped (eg if the road and rail widths were significantly different), so one gate on each pair had to move first before the other could be moved, so you can appreciate that the linkage could get very complicated!

[micknich2003]

Gate connections for a "Square Crossing".

[Richie Kynaston]

Thanks for the level crossing stuff guys.  Much appreciated, I have a bit clearer understanding now.  Also thanks to Phil for the PDF link, that made interesting reading.

 

Can anyone help on dimensions of this stuff at all?

[phil-b259]

Thanks for the level crossing stuff guys.  Much appreciated, I have a bit clearer understanding now.  Also thanks to Phil for the PDF link, that made interesting reading.

 

Can anyone help on dimensions of this stuff at all?

 

Sections 5.4a,  5.4b and 5.4c of the document I linked too give the key dimensions for cranks and rodding components.

Edited January 3, 2019 by phil-b259

[micknich2003]

Is the attached of any use? I have many others.

[Richie Kynaston]

Thanks for all the input guys. I am trying to help a mate of mine with creating some working point rodding and signal wire equipment for his new 16mm layout. I am sure he’ll probably start a thread shortly, but if not I’ll update this with how the S&T equipment is progressing!