Wednesday, 1 January 2014

The Lessons of the Point - Part 2

Before I go any further can I recommend David Nicolson's article on 7mm point building in the current MRJ. (Issues 227) Although about building S7 pointwork most of the content is equally applicable in 4mm scale. Had I delayed building my first turnout until after reading it and I would have avoided my big whoops.

Iain Rice's An Approach to Building Finescale Track has been my main guide up until now. Iain suggests, and I think it is a great idea when layout building, to build the longest possible track sections off the layout directly on the paper templates and with ballasting done before any rails are laid. At the end of construction this can be lifted as a unit and laid onto a resilient foam trackbed. I'm sure I can't be the only person to have suffered the frustration of what was a perfectly functioning RTR turnout becoming a major problem after ballasting so this approach sounds very attractive. However it is one of those things that in retrospect I wouldn't have chosen to do for my very first attempt at a turnout.  Too much information can be lost when the template is ballasted over even if you keep a spare copy and copy key information over to the edge of the template away from the ballasted area.

The specific problem I had was being caught out by a point that both Iain and David make. If the templates are going to form part of the final trackbed it is is important to use the right kind of paper.

Now normally my printer is loaded with good quality paper, though of differing sorts, because I use it for my job. So when I produced my first section of plain track using the "ballasting first" approach I didn't have any problems. What I'd forgotten was one of the step children had dumped an unwanted pack of cheap and cheerful paper into my paper tray.

This, by itself, nearly scuppered my attempt before it had started. The dilute PVA glue mix that had worked perfectly well for the plain track was absorbed very unevenly by this different paper. In some case the glue appeared to soak in and failed to bond any of the ballast. In other places the paper simply disintegrated.

So I re-ballasted and turned to the method I'd used on Apa, applying "Quick Shine" - a Klear type product, to ballast that was already in place. Unfortunately the top of the bottle came of and spilt it everywhere. This wouldn't have been so bad if I'd cut the TimberTracks base away from its supporting structure and cut the webs between the timbers. Because I hadn't done so. the soaked  plywood  curled away from the baseboard with the ends an inch or so above the trackbed.

At this point I came close to giving up.

A change of glue, reprinting the templates, cutting the point timbers free of their frame and the application of a lot of weight recovered the situation to some degree.

It was then that I managed to break the common crossing and had to resolder that as well.

I wasn't sure whether to begin construction by placing the common crossing or by laying the straight stock rail. I did the latter in the end but I'm still not sure it was the right approach.

After that construction actually became rather fun, although it is amazing how quickly you develop the ability to spot a dropped 4mm scale chair on a carpet.

Construction would certainly have been quicker if I'd had a better workflow for putting the chairs on  whilst also keeping an eye on which way round the keys were meant to go. However although the chairs are best slid on to the rail it is possible to also spring them on and off by flexing their base as long as you fix them to the timbers soon afterwards to avoid them dropping off. In the worst case scenario it is also quite easy to cut the chairs in half and apply a piece to each side if you don't discover the mistake early enough.

Costs are kept down by only supplying normal running chairs and slide chairs. Chairs to had the common crossing and the check rails in place are made by cutting these in half. One thing I didn't pick up from either the instructions or the template is when the best type of chair to cut was a normal keyed chair or a slide chair. I must go back and check if that was me missing something in the instructions or if it isn't covered by them. Other than that the trimming was much much easier than I'd expected.

The other thing that caught me out was not tinning the rail and attaching the  wires at the right point in construction. The tolerances on the fit between the chair and the rail ios quite tight and it didn't prove possible to slide a chair over a tinned section of rail. All that meant was I had to start threading  the chairs on from the other end.

Oh yes, and I half forgot to cut slots to allow for an under baseboard tie bar, but that was because I kept changing my mind about whether I was going to continue with the lift and shift idea post construction.

In the end I did, and despite the various escapades with glue it lifted away quite easily and has produced a surprisingly rigid and robust piece of trackwork. I still need to address the tie bar issue though.

Two final observations. You really can't have enough of two things - track gauges and weights!


  1. Considering the problems you encountered James I think you deserve a pat on the back for persevering, many would have thrown in the towel.

    Just a few observations if I may starting with underlay, having tried the C & L foam I found that I couldn't get on with it, no matter how I tried I just couldn't avoid a slight switch back effect especially at baseboard joints, so for Penhydd I returned to the tried and tested cork flooring tiles. Since then
    C & L have produced a rubberised cork underlay and that was my choice for Llangunllo. So far I am happy with the material which combines the best qualities of cork and foam, mind you it isn't cheap !

    Secondly I am not in favour of retaining the paper templates during track laying much preferring to carefully remove the template and install any track direct to the underlay. After all having taken care to build a level baseboard why introduce something such as paper between it and the track ? I also have concerns as to how the paper and it's adhesive will react in the long term no matter what quality it is.

    As regards chairs for the crossing nose etc, etc I just use a standard chair cut or adapted to suit, to aid the construction of complete crossing then the common crossing jig as described in the EMGS manual is a godsend, you will be turning out accurate crossings in no time and at a fraction of the cost of ready assembled ones, Part No. 8793(B6) . I also prefer to make my own switch blades as those produced by C & L still need extra filing and honing to produce a good fit, using the method in the society manual also results in a much stronger blade.

    I am sure you will soon be producing points with ease and I can tell you there is no better sight than watching your stock glide through a point constructed by yourself.

    Happy New Year,

    1. Geoff,

      Happy New Year.

      I have to say that once I'd realised that any mistakes with the chairs were capable of being rectified and weren't going to result in binning a relatively expensive C+L kit the process became rather enjoyable, almost therapeutic in fact.

      Interesting views on the underlay and retaining the paper template in place. I was surprised just how spongy the C+L foam is.

      I'm certain in my own mind now that building my own crossings and making my own switch blades is the way to go given the availability of the EMGS jigs.

    2. James,

      I was also surprised just how spongy the foam underlay was, if I remember correctly Iain Rice used the sort of material as used in Gym Mats.which is much firmer and I would say more suitable.
      Glad I'm not the only one who finds track building to be therapeutic, once in the groove it can be a very pleasant way to spend a few hours.