Modelling 4mm Conductor rail

On this page we review some of the products available to assist with representing the 3rd rail on a 4mm scale layout and provide some advice.

An element of compromise is usually necessary when modelling, particularly in smaller scales, so before we take a look at the products we raise a few issues about which we think you need to be aware:

Height and Location of the Conductor Rail

If you are adventurous and intending to have a fully working conductor rail system then accurate alignment both vertically and horizontally will be vital, but even if not, the pick-up beams and shoes on the rolling stock will need careful adjustment to prevent snagging on the conductor rail. For instance, the Webmaster found that when using Peco Individulay components on Peco Streamline code 100 track with the conductor rail at scale height the pick up shoes on Lima Class 73 locomotives were rewardingly accurately aligned horizontally with the conductor rail, but the pickup shoes contacting the conductor rail lifted the locomotive fractionally off the track so they would not run. It may be necessary to compromise and lower the conductor rail fractionally.

Narrow Gauge Considerations

Obviously OO gauge track is less than true scale width, and to a lesser extent so is EM gauge track. There will be a problem if rolling stock is fitted with accurate scale width bogies but running on OO gauge track because the pick-up beam/shoes fixed to such bogies will not align with the conductor rail, actually tracking outside the conductor rail. Not only does this look odd, but the beam/shoes might snag on the conductor rail, especially on tight curves and pointwork. Most ready to run stock intended for OO gauge makes a compromise with the width of its bogies, and, for instance, this is not a problem with Lima Class 73 locomotives nor Hornby Networkers. However, the bogies on Golden Arrow Productions Class 71 locomotives appear to be accurate scale width, which is ironic as these models were advertised as only made for OO gauge.

Strength/Resilience versus Accuracy and Looks

4mm scale conductor rail supports are rather small and thus prone to be delicate both to install and maintain. Fixing of the supports to sleeper ends and fixing of the conductor rail to the chairs may be weak and thus prone to damage by derailments and during track cleaning. So a compromise, trading slightly over scale components for strength might be worth considering or even sacrificing realistic looks all together by adopting a strong fixing method by not using scale supports.

Scratch Building

For strength and resilience at the cost of looks, fixing appropriately sized domed brass screws or brass tacks to sleeper ends and soldering the conductor rail to these is a consideration. Some modellers have even been known simply to glue the conductor rail to sleeper ends. These are likely to be the cheapest options!

Whitemetal Supports/Chairs

It is believed whitemetal casting of supports/chairs are either available or have been in the past, however we have been unable to locate any to appraise them.

Peco Individulay

Peco Individulay IL-120 supports/chairs and IL-1X code 60 rail have been available for many years. The s
upports/chairs are injection moulded in a slippery engineering plastic which makes them next to impossible to
bond to anything. They are also small and delicate items, prone to damage during installation and use. Packing washers are on the sprues to raise the supports/chairs to scale height when using code 100 track.

No jig is available for drilling mounting holes accurately into the sleeper ends.

For a full account of using these components, please click here

Scalefour Society/Exactoscale

Whilst these are undoubtedly the most realistic looking and accurate scale representations, every single support/chair you will need has first to be assembled from three parts – base, top (both plastic) and chair (metal). The parts are small so good manual dexterity and excellent eyesight, or assistance from magnification, are required. Construction of a jig to bend the chairs to the correct position is recommended. As bases and tops for both inside and outside supports for London Underground and for Southern Electric 3rd rail are supplied on each sprue, if you are only modelling the Southern there will be more parts left over than used. The parts are identified on the sprue but these markings are very light and the Webmaster had difficulty seeing them. No jig is available for drilling mounting holes accurately into the sleeper ends. The spigot to fix the base to the sleeper end is very short, thus the result will be delicate, however unlike Peco Individulay the supports/chairs can first be fixed to the sleepers and the the conductor rail then laid onto the chairs. The Scalefour Society has commissioned Exactoscale to produce accurate scale conductor rail supports said to be made of etched brass (but looks like etched Nickel Silver to me) and injection moulded plastic to go with its scale correct section 150 lb/yard conductor rail.  These supports can, according to construction, be used to represent outer third rail and lower centre 4th rail for London Underground tracks and low supports for Southern third rail.  Each packet provides between 60-70 supports, depending upon type being modelled. This is equivalent to at least 2.3 metres of plain 3rd rail track. End ramps, as nickel-silver castings, for Underground tracks are also available.  These components are only available via mail order to Scalefour Society members, however non members can buy them at  Scalefour Society exhibitions. These parts have been available since September 2005.

C&L Finescale

Recently introduced, C&L Finescale produce a number of components for 3rd and 4th conductor rails, including alignment jigs and side protection boards. For further details from their website, please click here.

Unlike with the Scalefour Societycomponents, with C&L Finescale Southern Electric 3rd rail and London Underground 3rd & 4th rail parts are available as separate packs. We will only review items relevant to the Southern Electric System.

Above left can be seen the jigs for aligning supports/chairs and side protection boards, plus lost wax brass supports/chairs. The supports/chairs are robust, maybe a tad over scale, and the feed provides a spigot that can be cut to length, potentially for fixing though the sleeper to the baseboard. So a firm fixing is assured, however the diameter of the spigot is roughly two thirds the width of an HO scale sleeper, i.e. Peco Streamline/Setrack, indeed most ready to run OO gauge track, so care needs to be taken when drilling to avoid splitting the sleeper. The conductor rail is fixed to the chairs after the supports/chairs have been installed, either by glue or solder. Currently the cost of supports/chairs works out at about £2.25 per foot.

Left can be seen side protection boards and brackets, the latter requiring spiking to sleepers.

We hope you have found this page to be of use. It is down to the modeller to decide what will work best for their requirements.

For advice on prototypical use of 3rd and 4th conductor rails, you are advised to view Russ Elliot’s authoritative and highly useful page of Third & Fourth Rail dimensions and settings.