Thursday, 6 December 2007

Flat Bottom Track

It's amazing that within the 'finescale' world of railway modelling that flat bottom (FB) track hasn't really been fully addressed. In the UK FB track has been commonplace on our mainlines since the 'fifties. It almost seems, at times, that when people imagine 'finescale' track, they think of bullhead (BH) track and pointwork. Why this should be I'm not entirely sure. A lot of historical modelling does require BH to be accurate, but many layouts have a need of FB track.

The visual difference between the two types of track is quite distinct, even on plain line -

This was taken by myself at the Hull Docks ABP/Network Rail boundary earlier this year; in the foreground is a recently laid FB track and beyond is old BH. This difference should be obvious to the observant modeller! The chairs/rail fixings, rail section, sleeper types and spacings all differ. FB track is very much an integral part of the modern railway, and something which, for me, needs to prominently feature on finescale layouts based in recent times.

For modellers one problem in accurately modelling FB S&C (switches and crossings) is that compared with some older BH pointwork, it's huge! High speed (100+ mph) pointwork is incredibly long, in 4mm scale some crossovers would be 12' or more in length! If you're used to PECO points, even slow speed FB (and a lot of BH!) pointwork will seem massive.

This is not to say that I'm dismissing PECO track completely, if you're working in 00, it's a very good and durable system, but we're often told that it's not that accurate, being HO. This is true,m it a slightly smaller scale, but it can be made to look very realistic for British FB track. I can do no better than suggest you have a look at the Wirral Finescale Railway Modeller's layout, Widnes Vine Yard which has track which is most pleasing in appearance. (It's also a very good layout overall too - at the Hull MRS' show in November I and a very good friend were watching, and agreed that Widnes shows the 'modern' railway we see everyday incredibly well - it's worth searching out when it's at a show!)

In the 'finer' gauges, EM and P4, we don't this option when it comes to FB track. We have to build our own. There are, however, two big problems. Firstly, the hardware isn't readily available, and what there is, is only a limited selection. And secondly, drawings are very thin on the ground. DEMU's society magazine, UPDate Issue 45, contained a useful drawing of a BV9.25 turnout but I haven't seen any other drawings published other than this one. You could probably build FB turnouts using BH templates, but it wouldn't be accurate (though having said that, London King's Cross is FB laid on the BH geometry, due to the cramped nature of the approach). If you work in the Rail industry you may be lucky enough to have access to official Network Rail drawings.

In this case, I'm not sure what to suggest - I do think it's an area DEMU should be addressing as soon as possible - though a CD of various drawings and diagrams has been available, they are not in a form which many people would be able to make use of. The problem is that accurate track like this is not a priority for a lot of people. Strangely, PECO are our saviour for many FB parts! The company who make track for the masses also produce a useful little range of parts in their 'Individulay' range for use with code 82 rail (which is 0,082" high and spot on for BS113A FB rail). Exactoscale produce their 'Fastrack', one type is concrete sleepering for FB plain line. it's not much, but it's a start!

With an eye to future layout projects, I wanted to try to see just what I could achieve using the parts I've mentioned. The first thing I did was to track down a suitable drawing - I used a copy of the NR drawing for a CV 9.25 & CVS 9.25 SINGLE TURNOUTS AND CROSSOVER, which includes details of a crossover and various types of crossings (this is the correct term for what many people call the 'frog'!). As an aside, I obtained the drawing by official means. I reduced it to scale size and mounted a full crossover on artist's mounting board which in turn was fixed to a 3' shelf. This would provide a good solid base for this test piece - check the shelf isn't warped though!

I placed the Class 66 in the middle to give some idea of size; remember this is quite a small example of FB pointwork! Despite this, the appearance, even at this early stage, is rather pleasing. The loco's size looks 'right' when compared with the size of the crossover. This is one of the attractions of getting things right for me. The brown card is really there to provide a lift for when the track is ballasted, other than this is isn't really needed. I can get away with such a thick plank because I won't be wiring the track or needing anything underneath.

The drawing I have shows all the information you should ever need! It provides far more than modellers need to know! In order to interpret the drawings, good photographs will be needed - these will help with positioning the different types of fixings too.

I decided that my crossover would have concrete bearers, so I used Evergreen styrene strip for this - no one makes concrete bearers anyway! And it's much cheaper than moulded timbers, so it a texture was added with course sandpaper I'm sure this product would work well as timber - but I'd be tempted to use thin ply for this. One thing to remember is that concrete bearers have chamfered edges, which can be tedious, but looks so much better than sharp edges! I'm only part way through adding the bearers it can be quite repetitive! But strangely relaxing at the same time.

Once they're all fixed in place I will sand them down to ensure that they provide a good and level base on to begin adding the rail and fixings. The plain line will be added last - I'm not sure if the Exactoscale sleepers will need any packing to match the height of the pointwork - I am, of course, screwed now if the crossover sits lower than the plain line! But I've made an educated guess that this won't be the case, well I hope not!

As progress is made I will be adding updates here, it should certainly be an interesting exercise.

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