What Is EM?

If you’re interested in improving the look of your models or if you’re contemplating construction for the first time,  The E.M. Gauge Society is here to help you.

If you already model to EM or P4 standards, membership of the Society delivers significant benefits to railway modellers.

Why 4mm scale?

In the years which immediately followed the First World War, railway modelling began to appeal to many more than the few who had tasted its pleasures in the earlier times.

The popular size was gauge 0 with a scale of 7mm to the foot. In the mass of small houses being built at that time, this meant there was little chance of constructing anything which could pretend to be a representative layout.

The solution was to change the scale, and a size half that of gauge 0 was the obvious choice. The electric motor technology of the age prevented anything smaller. These motors were large by modern standards and the drive was transmitted through in-line spur gears. The new scale was known as H0 (half 0) at 3.5mm to 1 foot. Whilst Continental and American locomotive boilers could accommodate the motor armatures and magnets, the restrictions of the British loading gauge and typically small boilered locomotives, caused considerable trouble.

The British answer was to increase the scale to 4mm to 1 foot (76.2 to 1). The Europeans and Americans stuck to their H0 and, whilst modern techniques can easily provide small enough motors, the British have remained faithful to their own 4mm scale.

Why 00 gauge?

Having decided to use 4mm as the scale, the problem was that no manufacturers produced a proprietary 4mm scale track. Continental imports were for 3.5mm scale, requiring the British wheels to be moved “in” to run on the smaller scale (gauge) track. There was also a belief that the wheel treads had to be of “steam roller” proportions if the stock was to remain on the rails. By setting the wheels further back than they should be, this function was obtained. The 3.5mm scale track gauge is 16.5mm, and for want of a designation, the mixture of 4mm scale locomotives running on 3.5mm scale track work was called 00.

The birth of EM.

To rectify this anomaly, a wider track gauge was adopted by a number of individual modellers, each using a variety of methods to build their own tracks.

The British Railway Modelling Standards Bureau (BRMSB) finally established the gauge during the Second World War. They set a standard of 18mm gauge with a specific wheel profile. Regrettably, once supplies returned to something like peacetime normality, the trade continued with the 00 syndrome, and the E.M. Gauge Society was formed in 1955 with the object of persuading them to adopt the EM concept.

For a variety of reasons, history shows us that the more influential suppliers remained unconvinced. In 1972, the Society embarked on a policy of supplying the missing goods as well as know-how. This enabled those who wanted to improve the look of their models to do so. Again, due to improvements in technology and the ability to draw up a closer standard for all the smaller specialist manufacturers, the track gauge of 18.2mm was officially adopted. Many of these small manufacturers are now members of the E.M. Gauge Society.

The expansion continued and to provide the necessary financial and legal protection to its members a Limited Company was formed in 1984.

Conversion to EM.

Many of the components used to build to 4mm fine scale standards can be bought from local model shops and specialist suppliers. Workers in EM can use wheels such as those from Alan Gibson, Kean-Maygib, Ultrascale, Sharman and Romford. The conversion of many locomotives, both ready-to-run and kit-constructed, is easily achieved by using longer axles and spacing washers between the wheels and the frames. Proprietary rolling stock can be changed for little more than the cost of new wheels. The wheels and axles provided by the Society are a direct substitution for the proprietary wagon and coach ranges.

In addition, the E.M. Gauge Society caters for members who work to P4 standards where the track gauge is 18.83mm and a specific wheel profile must be used with tighter crossing flangeway and check-rail clearances.

Obviously your track will have to be re-laid and the Society specialises in the provision of track building components. A set of full size track and turnout plans (either to EM or 18.83mm gauge) is given free to all members to form the basis of constructing trackwork and building jigs. Similarly, a full set of wiring diagrams is given free at time of joining.

There are several plastic-based plain track proprietary systems, which are also compatible with the hand built turnouts. Some systems can also provide the basic requirements for turnout construction.

Most of the current, ready to run proprietary 00 locomotives, kits, coaches and wagons can be converted to run on the wider rails, quite often by just using longer axles, spacing washers and a very basic tool kit.

The Society Trade Officer holds a comprehensive stock of all the parts needed to carry out the work at home on the kitchen table. A postal service is available but all the items are on sale at the various EM events. All the Society events are supported by a large number of specialist traders. Members can discuss their problems with the actual manufacturers and with fellow modellers attending events. No one person is expert in all things, so there is a ready forum for the exchange of ideas and information.

Society Organisation.

The EMGS is run by a Board of Directors elected at the AGM, who are all dedicated model railway enthusiasts independent of any outside influence. The Society’s financial year runs from the 1st of September to 31st August. Members joining late in the year receive all publications currently available.

If you are interested in becoming a member please complete a membership application form and send it direct to the Membership Secretary.

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