Level Crossing Operating Mechanisms

mounting?

advance for

Sorry, are you talking about 'gates' or 'barriers', your comment regarding full and half gates is somewhat confusing! If you are talking about gates then why not use Macano (sp?) ?

Archie, Are we talking Lifting Barriers or swinging gates?

I would also be interested in the replies....

Andy Sollis CVMRD

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Our club is thinking of adding one to a section of plain track on one of our layouts. We have not quite decided yet whether this crossing should be of the full gate or half gate opening and closing type. Thanks in advance for any assistance folks.

Archie

I believe that 'gates' refers to the method of blocking the road whilst leaving the rail line open and v.v. There were usually 2 full gates, each covering the full width of the road, or 4 half gates..........................Most half gates were designed to block the railway line(s) in the same fashion as they did the road, but some, due to the site, overlapped when blocking the railway.

Barriers, as far as I'm aware, only ever blocked the road.

-- Steve

For lifting barriers check out Memory Wire at

Click on Modelling Applications.

I've been trying to figure out how to use it for swing gates...

Some single-track crossings had a pair of single gates, operated independently - usually manually. Surviving examples at Damems and Oakworth on the KWVR.

Me too!!!!!!!!!!!

Cams on a plywood disk.

Are these gates or booms, to be operated automatically by the trains, or manually by an operator? If swinging gates, perhaps a simple bevel gear set with Meccano chain and sprockets, all coming out to a crank handle at the edge of the layout table could do the job. From my memory of the local swinging gates, now long gone, they moved rather jerkily, the crank handle operation could give a similar motion. Regards, Bill.

gates, each

block the

Yes, but the way they operate is the same, so this still leaves the question as to why the OP mentioned it if it didn't matter.

You just need to convert the linear motion of the wire into the rotary motion of the gates. Now, where have I seen that before...

MBQ

I'm racking my brains to think of how to do it.

R.

A google search produced this gem from this newsgroup in 2002, if it's of any help :-)

Dammit, are my puns *that* obscure?!

But thanks for the reference, anyhow...

R.

No :-)

But it got me thinking, and googling, and the fact that a similar thread had come up before, as they do.

A case of the wheel goes around.... ?!!

My prototype only had booms, but it would appear to me that hand operated swinging gates would be moved one at a time. With a single gate on either side of the track, one would have to be moved before the other or they would collide in the middle.

- That would require either two (gear) mechanisims, two motors and switching so the first one would switch itself off and the other one on, and then the second one would switch itself off and the other one on through a diode ready for the opposite motion.

- For hand crank operation, a simple cord drum, cords, crank on gate shaft, weight for return action should do the job. The gate shft cranks could be made with a pin and the cord crank could sit loosly on the shaft below with a large cutaway so that only half the movement affected the gate.

Four gates would be more complicated - did they all move at once, or one at a time in sequence? Given that the crossing gates formed a square, a revolving (plywood) disk with cams on the outer edge could drive sprung cranks, either in sequence or all together.

A crank sits on the gate shaft under the baseboard - a light spring pulls the crank and gate to the "rest" position - the memory wire pulls the crank against the spring to move the gates.

When I worked in the S&T on the section between Havant and Chichester the crossing at Fishbourne, Bosham and Southborne all had wheel operated gates from the signal box and they all moved at the same time. There was some quite complicated arrangements of cranks to achieve this. As opposed to gates that were locked by lever operation and required the gatekeeper to either open or close them one at a time.

Chris

Yes, I was a participant in that thread; I haven't made much progress...

The challenge is making four gates move at once using the minimum amount of memory wire, which is quite expensive.

Here is a point motor design I came up with for use with Hornby or Peco points with over-centre springs. It doesn't require a continuous current to hold the blades open (or closed).

Yes, but you'd need four of them for a double-track crossing.