Reconstruction work at Dunalistair

[tedp]

After having been laid low with the 'flu for a week I decided I could do with a small modelling project to aid my recovery. I had been looking with distaste at the old Arnold point in the coal jetty at Dunalistair for some time, and I decided to finally replace it. For this, the stripwood decking had to be torn up. This proved to be rather difficult as all had been stuck together with PVA glue, back in the 1980s when the jetty had been made.

Here is a photo of the decking being torn to pieces. Eagle-eyed readers may spot the hoax: the Peco point by this time had been put in already but naturally I forgot to take photos before taking the old one out. The damage to the jetty timbers can be clearly seen however.



In this shot you can see Lord Dunalistair having a look at the work in progress. As usual the old busybody is clad in his black suit and accompanied by his umbrella.



The Peco 12" radius point was inserted with some difficulty. I had to cut bits of rail off each of the jetty tracks and then soldered the point in place. The front track had to be bent a little to accommodate the different curvature of the Peco point. I soldered tiny pins to the rail sides for improved strength. I needed to tweak the gauge on the curved track a little as it tended to spread. It doesn't look pretty but the track has become quite smooth and the mess will be covered up with planking.



The toe end of the point was extended with lengths of rail glued to ply sleepers. These fit neatly on to the stub end of the jetty road which curves around the Fisherman's Rest:



After testing the track using the six-wheel West Clare brake, the decking was patched up by gluing in the old deck sections and filling in most of the holes. In addition, a Peco point lever was shoehorned in. Note that I didn't add any point blade switching or a point motor, as there never was one and contrary to general opinion I feel confident the blade switching will do its work.





To be continued.

[tedp]

Part 2

Even now this Colin Ashby wagon fitted with Parkside wheels refused to run over the point. The cause proved to be a back to back problem on the wheels which were 7.2mm apart. Investigation of the new Peco 12" radius points proved they have a back to back between the wing rails and the check rails of exactly 7.2mm. So there is no free space left for the flanges to pass through especially if they are at an angle on the curved section of the point.

The Parkside wheels pass through the older Peco points without problem. The flangeway in the frog of the new Peco points is about 0.9mm as opposed to 1.1mm in the older points.



Most of my stock uses continental N gauge wheels which have a back to back of about 7.5mm. I have since made a 7.4mm back to back gauge from brass bar to re-set all my Parkside Dundas wheels with.



This photo shows the deck completed with stripwood and balsa fill pieces next to the rails. These were pre-painted, then the point blades and some of the detail were masked with tape and a light dusting of matt black spray wafted over it to represent the coal dust.



Lord D and the foreman observing the running trials with a few coal wagons:





The chap in the green yacht by the way is a caricature of myself in my first 18ft boat. And I fear Brian M will have something to say about the alignment of the track in this view  ;)  :



I added a safety rail next to the point lever as this is right over a 20ft plunge into the harbour:



Finally, comparing the removed Arnold point and the one that replaced it:



There will be more track reconstruction at Dunalistair in the future, but it may take a while. At that time I will revive this thread.

[Isle of Stoner]

Good work, tricky thing to do.

John W

[JulienW]

Don't worry about the track work Ted - there is a section much like yours at the (standard gauge) harbour station at Weymouth!

[tedp]

 ;D  it's not the track that worries me, as that works all right.  ::)

[tedp]

Last winter when I replaced the point on the coal jetty, I didn't install a point lever, apart from a dummy Peco one. Since the point needs to be operated regularly, I decided to replace the dummy lever with a real one.

This is a very ancient overscale item but the smallest I could muster. I made an elongated hole in the operating bar, which engages with the stud on the end of the point's tie bar. The elongated hole was needed to account for the difference in throw of the point and the lever. Here is the result - I see I still need to fill in a few tiny gaps in the planking, but otherwise all is working as it should.

[tedp]

It is rather overscale. So I painted it black now and it looks much better.

[tedp]

It is about time to pick up this thread again. I haven't ripped up any track in Dunalistair yet and it will probably take some time before I do.

One reason is that replacing the pointwork will also need me to re-site or even replace the point motors. If I replace them I may need to use servo motors instead, which in turn will mean changes to the wiring. I'm not yet prepared to do so at short notice. Furthermore I will need to scratchbuild a diamond crossing to replace the old one, which has a slightly different angle and also is far too coarse in the flangeways. For the moment, I jury-rigged the old track where the gauge was too narrow, and it works.

The easiest way to prepare the way is to copy prototype railway practice, where pointwork often is built up as a kit of parts which is assembled on site, and later inserted into the track layout. First, I checked on the geometry of the Peco 12" points. These have a slightly bigger angle than the Fleischmann ones. If necessary it is possible to tweak the curved rails where they leave the crossing (aka the frog). But if I don't need to do so, I will leave them.

I laid out the points in the spot where I will position them as follows. Here are the two cross-overs between the platform road and the centre road.





Next, there are the points leading to the existing diamond crossing. Here immediately the different approach angle is apparent. When I install a new diamond crossing, the inset track will partly have to be lifted.



Measuring the length of the crossover track between the points.



And here it is installed, with an insulating joiner next to each point. Instead of cutting both rails at the centre as in the present track, I have staggered the insulated joints. Note that the connecting rails will be shorter than they are in the present layout, due to the different angle of the points. The metal joiners have been reinforced by a light touch of the soldering iron.





Next, the length of track between the two facing points in the harbour road is cut. Note that I removed part of the sleeper web, so the rail can be cut safely. There will be a single insulator between the points. I will add a diagram of the points and the diamond crossing at the end of this post.





Here is the new complex in the harbour road, where a diamond crossing will be added. Again, note the different angle.



Finally, the point into the goods shed is added, with a short length of track separating it from the toe of the point leading to the coal jetty.



For the moment this will have to suffice - the diamond crossing will be built up as soon as I can spare more time! The built-up assemblies were put away in a drawer. Here is what I built tonight.



Wiring diagram for the diamond crossing:

[clayliner]

I confess I'm disappointed,Ted - those crossovers in the second photo were just crying out for a nice r*v*rs* c*rv* between them...  ;)

David

[tedp]

Oh, but I'm a true believer - didn't you know?  ::)

Today I decided I would have a go at that diamond crossing in the harbour tracks. It is situated in the coal pier siding, which crosses the quay siding halfway in the pavement of the access road. The present crossing will have to be dug up when the track is replaced. Since the original material of the pavement isn't available any more, I will have to think of something else - possibly wooden inserts.

The old crossing was built up on a piece of printed circuit board. The methods I used at the time were crude, so this time I decided to try and build a proper crossing. Note that this is an experiment which I hope will work as I planned! Even though I'm a long time modeller, I'm still trying new techniques. The way to build it up was described by the late Don Boreham in his 'Narrow Gauge Modelling' book. The rails are filed to fit to each other at an angle. After fitting the rails together, the flangeways must be cut. Here is the diagram from his book.



The first thing you do is prepare the PC board. This is about 35x45mm. The copper surface is cut through in preparation for the rails to be soldered on. This was done with a cutting disc in a mini drill.



Then I established a reference rail to fit all the other rails to. The reference rail is aligned with the track that will remain in place. First, the points are aligned over the main harbour track, then a single piece of rail is fitted to one of the points, and aligned with the corresponding rail in the inset track on the quay.



This first rail is soldered on to the copper surface. You need a pretty big soldering iron to do so - my 25W iron just manages to heat it well enough to fit the rail - the soldering isn't as neat as I would like, but it works. I spot solder it at one end, then tweak it into place at the other end and spot solder it again. The first spot is then heated so the tension comes off the rail. Finally, the entire length is flooded with flux and the entire rail is soldered in place.

Next, the reference rail from the other point is cut to size, filed to a chamfer and joined to the first reference rail. The rail ends have to be recessed at the bottom to take the foot of the rail section into account - otherwise a gap would result. The second reference rail is continued beyond the crossing (bottom left). This again is aligned to the appropriate rail in the other siding.

I had to slightly bend the reference rails to align them to the siding rails, due to the slightly different point angles.



With the reference rails aligned, the other rails can be cut to size and fitted into place on the workbench, each 9mm from the reference rail. The 9mm track gauge was used often to check the gauge. Step by step the rail was fitted into place, spot soldering at one end first, then aligning it to the reference rail and straightening it out. Note the rail in the third photo below, which is only spot soldered at both ends as I check the gauge.







Finally, the entire assembly is laid on the layout and checked against the existing track. I also put loco 17 (with the thick Arnold flanges) on the crossing to see if it would fit without binding. And it did!   ;D





Next, as soon as I can find the time, I will fit the wing rails to the crossings and start filing the gaps as in Don Boreham's diagram. If you file the gaps to the most common depth of the wheel flanges, the stock will run across without bumping. Also, note that the rails will have to be gapped between each of the four crossings.

To be continued.

[Krizzy]

Bloomi' heck Ted, you must be a masochist to do a crossing like that! Or better still how many bottles of scotch are you going through while working away on the crossing. Dedication is probably more correct. Thanks for keeping us enthralled with your super efforts to keep the C&D running in tip top condition.

Roger

[tedp]

 ;D  I will have to make it work first. If it flops, I'm out on a limb and you can all share my discomfort...   ::)

[tedp]

Well - today was an unexpected off day. I had expected to do some work on a new door in the living room, but it hadn't arrived yet. So I did some track construction. I largely completed the soldered diamond crossing.

First, I added the wing rails. These were soldered on using low melt solder to avoid disturbing the other solder joins. Note the right lower wing rail, which hasn't yet been soldered. The procedure is to make it to size, then drip a little flux under it and lay a tiny piece of solder wire against it. Touching it with the soldering iron results in the piece of rail being fixed to the copper clad surface.



Here is a close-up of a rail end. This is chamfered and in addition, a notch is filed in the end where it has to slot against the foot of another rail.



Here are two photos of the assembly largely completed, but still without the flangeways having been cut. The back to back measurement between the wing rails and the check rails is about 7.2mm.





Finally, the completed assembly. The flangeways have been cut, and in addition two brass support pads have been fitted in the angle of two crossings where the flange needs to be supported over a greater length. The cutting of the flangeways is done with a cutting disc at low speed, with some of the finer work completed using a Roco track saw. It has to be done with care, otherwise the passage is too deep and the wheels wil start to drop into it. The flanges of 'William Wallace' still stick a little, but I expect that they will improve with careful fettling, and polishing of all the sharp edges.



By the way, I also cut the gaps to insulate the four crossings. For this I used a track saw - a cutting disc is too coarse. It was rather a difficult job, and one piece of rail came off which had to be re-soldered.

The interior of the diamond will have to be fitted with check rails also, but I plan to make these out of plastic. They are less important and they span four insulated areas...

[tedp]

Today I wired up the diamond crossing, after fitting the necessary insulating rail joiners. Here is how it looks now.



Compare to the diagram. The red wires in the photo are fitted to the curved stock rails of the points, just out of view. The wires seem to be connected in a different way from the diagram, but I assure you they're not! Green and yellow take the place of blue and green in the diagram - sorry I used different colours from the diagram here. Note that I soldered the connections to the copper surface of the PC board. After fitting all the wires I tested for a short circuit in the assembly, and I found one. This was eliminated by scratching out the gaps in the rails and the PC board.



I also fitted the assembly in a test rig with stub tracks to both ends and tested several locos and items of rolling stock over the diamond crossing. All ran satisfactorily, although I need to deepen some of the flangeways by a fraction. More later.

[WALLSHIRTS]

What rail did you use for this?
Mal.