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G Scale Standards |
| SCALE/GAUGE NAME | 'G' Scale | Prototype |
|---|---|---|
| SCALE | 1:22.5 | 1:1 |
| TRACK | ||
| Track gauge | 45mm | 3ft 4in (1012mm) |
| Rail profile - Gauge 1 | Tenmille Scale Brass Flat Bottom or Bullhead, or Cliff Barker. Code 180 or 200, | Grooved girder |
| Rail profile - LGB | LGB or Peco Code 250 | Grooved girder |
| Groove width, straight track - Gauge 1 | 2.25mm | 1 1/4in to 1 5/8in (32mm-41mm) |
| Groove width, straight track - LGB | 3mm | 1 1/4in to 1 5/8in (32mm-41mm) |
| Groove width, curved track - Gauge 1 | 2.75mm | 1 1/2in to 1 3/4in (38mm-44mm) |
| Groove width, curved track - Gauge 1 | 3.5mm | 1 1/2in to 1 3/4in (38mm-44mm) |
| Minimum radius curve, older trams | 600mm | 45ft (14 metres) |
| Minimum radius curve, modern trams | 710mm | 52ft (16 metres) |
| Double track distance apart (track centre lines) | 125mm Minimum | 9ft 3in (min) (2.82 metres) |
| WHEELS | ||
| Recommended either to Gauge 1 commercial available wheelsets | Gauge 1 Commercially available wheelsets | ------ |
| OR to "G" Gauge commercially available wheelsets. | "G" Gauge Commercially available wheelsets | ------ |
| Back to back Gauge 1 | 41.5mm | ------ |
| Back to back LGB | 39.5mm | ------ |
| Axle diameter Gauge 1 | 4.75mm (Slaters) | ------ |
| Axle diameter LGB | 6mm | ------ |
| OVERHEAD | ||
| Minimum height above road (scale) | 270mm | 20ft (6.1 metres) |
| Height for LGB overhead above rail | 226mm | ------ |
| Wire type and diameter | Phosphor - bronze 20swg or 0.8mm copper | Copper 0.32in |
| Wire type and diameter LGB | Plated steel 2mm dia | ----- |
| Length of traction pole above ground (scale) | 340mm | 25ft (7.6 metres) |
| Length of traction pole LGB | 300mm | ------ |
| Distance apart of traction poles on straight track | 700mm (average) | 120ft(max) (36 metres) |
| Distance apart of traction poles on straight track LGB | 600mm | ------ |
| Distance apart of traction poles on curved track | As required | As required |
| Position of overhead wire relative to track, trolley poles. Straight track | Over centre | Over centre |
| Position of overhead wire relative to track, trolley poles and pantographs centrally mounted on long bogie cars (like Blackpool). Curved track. | Over inner rail | To a complex formula |
| Position of overhead wire relative to track, bows and pantographs over bogie pivots. All track. | Over centre | Over centre |
NOTES
'G' gauge is a scale gauge ratio that was developed by LGB in the 1970's. It is a narrow gauge system modelled on metre gauge railways and was originally designed for garden use. 1:22.5 scale is effectively Gauge 3 Scale. Those modelling standard gauge Gauge 3 (1:22.6) trams are advised to use G Scale tramway standards.
TRACK
For scratch building track then the Tenmille brass flat bottom or bullhead rail is recommended, either soldered to large copperclad sleepers or directly to brass countersunk screws fixed into the baseboard at appropriate places or nailing with flat head ring pins onto the rail flanges at appropriate places. Peco offer a flexible Gauge 1 track and parts for points. Cliff Barker does fine scale track. Many modellers using the coarser wheel standards make use of commercially made track. Peco manufacture gauge 1 flexible track and points this is 45mm gauge suitable for G gauge. LGB and Peco also offer 'G' gauge ready to run track. G gauge points are also available by both these manufacturers.
Many modellers use the two rail system of power supply. Either this or live overhead will need the rails to be bonded. For live overhead supply the running rails can be electrically connected.
WHEELS
While the width of the tramcar wheel is much less than a railway wheel, with a smaller flange width and depth, in 'G' gauge modelling it is usual to use the commercially produced wheel sets. Gauge 1 wheels are a little over size, but are recommended but will need the back to back measurement opened to 41.5mm. Some modellers use the LGB standards which are rather too large, but will be compatible with Peco and LGB pointwork. Modellers mixing scratch built tramcars with LGB and Bachmann commercial models will need to adjust their track groove width to accommodate the more coarse scale products.
OVERHEAD
LGB make an overhead system for their trams, but it is very much lower than scale. It is impossible to get a double deck tramcar under it. It is not difficult to build your own overhead as there are books and articles available to show you how. Generally the spacing of overhead poles on model tramway layouts is much closer than the prototype. This creates an illusion of greater space and is best achieved by spacing the poles so that the model "looks right".
POWER SUPPLY
The standard power supply is 12 volts DC, using model railway controllers. The recommended controller is the electronic feedback type with panel mounted or handheld (HH) controllers from Gaugemaster or Modelex. They require a separate 16 volt AC supply from a transformer, although some manufacturers have their transformers embedded in the unit. The LGB controllers are rated at 18 volts DC, but in practice are compatible with other products mentioned in this Standards Sheet.
In 2 rail supply each rail will have its own wire connection to the controller, whereas if you are operating on the overhead principle one wire will go to the overhead and the other to the rails. In each case you will divide the electric supply by cutting the rails into separate sections, each section being supplied through an on/off switch to allow control of different trams on each section. DCC can be used on either 2 rail or overhead systems, in both cases there are no need for sections.
LINKS FOR WHERE TO GET EVERYTHING
List of TLRS standards for other scales.
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