Reconstruction work at Dunalistair

[tedp]

By now this has almost turned into a signalling thread!

Today I completed the work on the signalling and track of Dunalistair - the station throat and the main line needed little work, apart from the signalling detail. Even though I had anticipated a lot of work, I grossly underestimated it. The main danger is that you damage all the structures and scenery that have to stay in place - working signals, lamp posts, fences and telegraph poles are the most likely candidates. And due to the awkward situation of the layout I had to stand in an uncomfortable attitude time and again.



Anyway, all has been done now. I will describe the work step by step, then add some photos of the largely completed scene. Yesterday I had prepared the route for the operating wires along the track, drilling pilot holes for the pins used as wire stanchions and testing the clearance.

Yesterday night, as we sat watching a TV film, I made up a number of pulley stacks similar to the ones made before. This time I needed no less than seven two-tier pulleys. The process has been described a few pages back. Fitting them to the layout this morning was a matter of careful alignment to prevent the widest stock hitting them on the tight curve of the main line. The NWNGR type six-wheeler with its deep frames has the worst overhang.



Here is an image showing most of the pulleys and the way they were laid out to guide the wires to the signals. After they were glued down, rigging them with fishing line proved very similar to rigging a ship model. The fishing line is rather stiff though, so it needs careful gluing, often using contact glue first before applying cyanoacrylate.



In the next photo note how I temporarily tensioned the line by tying it to a pin inserted in the scenery - there still is a tiny pinhole in the road!



In the next photo, I have filled in the damage spots made in the scenery to glue down the point rods. Note that the rods and the wires are interrupted at the baseboard break - an unfortunate but necessary measure.



An overview of the signalling arrangements near the starting signals and the (dummy) shunt ahead signals, after the wires and pulleys were painted.



After all the work done, I'm not displeased with the result shown in these detail shots.





Next, a view of the facing point lock and operating arrangement at station throat. The actual operating rod for the point comes in from the bank behind the railway - it's a steel wire hiding under the plastic crank! The point motor is under the lighthouse.

Also note the wires to the home bracket on the headland - these terminate in pulleys leading the wires to the signal post. No pulleys actually mounted yet on the post itself.





Note that some improvement on the buildings and scenery is planned as well. But first I will operate the layout for some time so the new track is proven and any remaining glitches ironed out. One of these is the track gap between the two baseboard units which seems to have increased over the years. This has to be re-set so the transition is smoother than it is now.

Here is the Kitson and the L&MVR coach on a special working.



And a goods train hauled by William Wallace, approaching the catch point on the harbour road.



And some final views of the goods train entering the station.





I still need to think of a lever frame at the Foundry siding, and the associated rods and wires. But for the moment I will halt the project and enjoy the results of this two-year project for a while!

[tedp]

This should really go in the 'signalling and operation' chapter.

An electrician's lot

Warning: this post may not be for you if you don't like wiring!

A few days ago a drive pin broke on a point motor under Dunalistair. It was this one, fitted with a brass drive pin:



I was just trial running the little Backwoods Barclay that I repaired the chassis on, when I noticed the point to the coal jetty wouldn't throw when I flicked the switch. A moment later I heard something tiny drop into the cabinet below and I thought 'noooooo....!'

Luckily the point motor could just be reached - they are stuck to the underside of the baseboard with contact (impact) glue, which can be coaxed to 'give' if you slowly apply a force. The point motor tilted out of the way and I could replace the drive pin, this time soldering it to the bottom end of a new brass tube, so there was a little more free play at the top end of the tube. The pin looked like having failed through metal fatigue. I refitted the point motor, gluing it in after I managed to fiddle the new drive pin into the point's tie bar and get the microswitch lever in place - this is pressed on by the drive pin if you throw the point.

Test running over the point proved it was all right, both on the curved and straight roads.I ran the Barclay up the line with a load on to see how it would hold up. It went all right till I cleared the up starter at Rae Bridge for it to continue through the Gorge and up to Inverlochan.

The train refused to move past the signal, and after investigations it proved to be the case that the track relay at Rae Bridge didn't click in as it should. For those electrically minded, here is a diagram:


The power to the relay at Rae Bridge is controlled by a relay contact at Inverlochan - follow the blue circuit at the bottom from where it says 'signal track control switch', bottom right. The circuit is routed through the relay on the left, then returns to the coil of the relay on the right.

After establishing the cause of the power failure, I got out the diagrams, which (though out of date) mentioned the colours of the wires under the layout. I traced the control circuit back to a screw terminal fitted to the support frame of Dunalistair, next to the point motor I had just replaced! And lo and behold, there was a wire loose which had been nicked out of the terminal.

To give you an idea of the cramped place I had to work in, here is a photo - various pillows stuffed in the bottom to prevent me hurting my back. I could just wriggle in and out, not a bad feat at age 64. Note the 230V lead of a LED spot which I had clamped to a frame under the layout:



And here is the underside of the layout that I had to work on. The offending point motor is in the shadows to the left, and the wire I pulled loose just to the left of the picture, indicated by the arrow:



Well, all was done, I thought. But that d*mned little Barclay must have been jinxed, because after returning to Dunalistair I noticed it wouldn't run over the point at the other end of the diamond crossing, the one leading to the harbour siding. It stuck every time I tried. I had just re-packed the cabinet that I had worked in, so all came out again and I investigated. You'll see the red-ringed area to the right of the photo. The microswitch has a grey and a purple lead to the screw terminal just to the left of it. The grey lead was loose, and when I re-fitted it, it shorted out the point in one position!

Eventually, the problem was traced to the solder joint on the arm of the microswitch which was threatening to come adrift. I superglued it as I didn't fancy soldering over my face without room to move. And yes... I also stuck the switch lever to the casing grrrrr.

I removed the switch, upon which the point worked fine and the blades switched the power without problem. Probably the grey wire had been off from the beginning so I didn't notice the switch that had failed!

Anyway, this morning I unstuck the lever and tested the switch, found it was all right and replaced it. The frog of the point now finally has a working backup switch!