Modelling the broad gauge is very similar to any other model railway, excepting the track spacing, and the more difficult added interest if intending to include sections of mixed gauge track.
The BGS can supply scale rail, but not ready to run track work, which is why these standards are so important.
The Society's locomotive and wagon kits are also designed to these dimensions.
BGS - Modelling Track & Wheel Standards.
Shortly after the formation of the Broad Gauge Society, and consultation with the 2mm Association, EM Gauge Society, Scalefour Society, and Scaleseven Group, - a set of modelling standards were collated. They have been adopted by the vast majority of broad gauge modellers, and the Society's 'back-to-back' gauges are manufactured to these standards.
BG2 - These standards are based on those used by the 2mm Scale Association, and are compatible with their standard gauge dimensions. Modellers who wish to include mixed track gauge must use those standards - BG2 is not compatible with N gauge.
BG4 - 4mm scale modelling is often a compromise, as the ready-to-run 'OO' market has always produced models that are grossly under gauge. So there have been offshoots to the EM and P4 gauges for the more purist modellers.
If wishing to run broad gauge with 'OO' as a mixed gauge line, it may be better to adopt a less than scale track for the broad gauge, as the 'OO' is so under scale it will look wrong. A gauge of 25mm would be in correct proportion, but this is likely to cause problems with inside framed stock, and is not recommended.
The broad gauge look is very distinctive, and the Society adopted 4mm exact scale. Using the Society's gauges is the surest way to produce track and rolling stock which is compatible with that produced by other members. The choice between EM and P4 is for the modeller; the Committee originally recommended P4 standards, and based on sales of the Society's gauges, around 75% of members have adopted them. If a modeller is already committed to P4 or EM for standard gauge, this would normally dictate the standard for broad gauge. P4 stock will run on an EM layout, but the reverse is less successful.
If starting from scratch, the P4 standard is recommended, for which gauges and wheels are available from the Society. Since ready to run track is not available, it will be much easier to lay new broad gauge track to P4 standards.
BG7 - These standards were adopted many years ago by the pioneers in 7mm scale broad gauge modelling, and have stood the test of time. Using this basis, a number of layouts have been built and exhibited, and the dimensions are recommended.
Some data sheets were prepared to fine scale standards using either 49mm gauge (O7), or 48mm gauge (R7). The latter was suggested as being in the correct ratio to 32mm standard gauge, but we are not aware of its use. As far as is knowm, virtually all BG7 modellers are using S7 (Scaleseven) standards.
The Society's standards are posted here for information, but this page is not intended to be exhaustive in its content. Artwork by John Boshier; text by Alan Garner.