Layout design: turnouts

Turnouts are the primary building blocks in any layout. The space which that layout occupies, the trains that can be run and the whole character of the layout depend on the type of turnout used. There are four options to consider.

Ready-made turnouts

A layout using ready-made turnouts is most easily designed full size on the baseboards, particularly if the manufacturer will supply full size drawings. If these are not obtainable, you might consider purchasing one of each type of turnout you require and using them to make a paper pattern that shows the size of the turnout and the locations of the rails at the end of each line. Such patterns can be photocopied to provide as many as you require for the layout. If you have access to a sufficiently large photocopier or scanner you can simply make photocopies of each turnout, but for O gauge the necessary equipment is more likely to be found in offices than in the home.

Alternatively, there are several software packages that can be used to design track layouts using commercial pointwork. It is important to ensure that you choose a package that handles the pointwork of the manufacturer you wish to use.

Using ready-made turnouts means being more limited in the design and appearance of the trackwork, but it is likely to be the quickest way to a working layout. Another advantage is that the layout can readily be altered and the components can be re-used.

Turnouts using commercial components

The components referred to here are particularly the switches and crossings, but may also include such things as pre-cut sleepers and tiebars. Full size drawings of turnouts of different radii or crossing angles may be available from suppliers or can be drawn using suitable software. If not the drawings will have to be made by hand.

Components made from plain rail on existing standard drawings

This differs from the preceding option only in that you make your own switches and crossings. This increases your choice of turnout design because you are not limited to what the trade can supply.

Components specifically tailored to the design of the layout

The three options above can all produce workable track layouts. One of the advantages of these options is that the turnouts can be built off-site under good conditions of access and lighting. The time involved in making pointwork can be reduced by the careful choice of standard dimensions and by following established procedures. However, in choosing any or all of them you can seriously limit the fluidity of your design. Turnouts based on the use of manufacturer’s standard switches and crossing angles tend not to sit comfortably into a freely curving main line and can require a lot of adjustments to the track plan. The layout is likely to need more than the minimum of space if appearance and performance are not to suffer. This has occurred on the prototype too: see Figure 1.

If turnouts are specifically tailored to fit the layout, the whole track layout can be planned so that curves and crossing angles make the best use of the space available while the whole looks pleasing and authentic.

Figure 1. Trying to squeeze a quart into a pint pot.

In some cases it will be feasible to build turnouts in situ. This can be advantageous, especially where a string of turnouts follow one another closely, they can then be smoothly fared, each one into its neighbours. In general there is then less risk of unwanted bumps and kinks occurring at joints.

Often however, it will be desirable or even essential that actual construction takes place on the bench. Then a removable drawing should be prepared in situ to be transferred to the bench for refinement and as a basis for construction. Before beginning to build however, put the completed drawing back into place on the layout top and make sure that it really does blend smoothly into the adjacent track. Careful checking is essential, rectification in position seldom produces sweet results. A refinement of this approach uses a sub-base, of for example 3mm MDF, on which has been drawn the outlines of the running rails and other features. On completion, the whole assembly can then be dropped into place and joined to adjacent track.

This article was originally written by the Technical Committee for the Gauge O Guild Manual. It was edited and adapted for the GOGWiki by Nick Baines.