TLRS TT Gauge Standards - British

SCALE/GAUGE NAME TT Gauge Prototype
SCALE1:1001:1
TRACK
Standard track gauge12mm4ft 8 1/2in
Rail profileCode 75Grooved girder
Groove width, straight track1.25mm1 1/4in
Groove width, curved track1.5mm1 1/2in
Minimum radius curve, older trams105mm (4in)45ft
Minimum radius curve, modern trams and large bogie cars135mm (5 1/4in)66ft
Double track distance apart (track centre lines)35mm (1 1/2in)8ft 6in
WHEELS
Recommended to "OO" gauge BRMSB standards (ie Jackson, Romford or Tenshodo).BRMSB------
Back to back10mm------
Axle diameter2mm------
OVERHEAD
Minimum height above road60mm20ft
Wire type and diameterNickel silver 0.3mmCopper 0.32in
Length of traction pole above ground80mm (3 1/4in)25ft
Distance apart of traction poles on straight track115mm (4 1/2in) average120ft(maximum)
Distance apart of traction poles on curved trackAs requiredAs required
Position of overhead wire relative to track, trolley poles. Straight trackOver centreOver centre
Position of overhead wire relative to track, trolley poles and pantographs centrally mounted on long bogie cars (like Blackpool). Curved track.Over inner railTo a complex formula
Position of overhead wire relative to track, bows and pantographs over bogie pivots. All track.Over centreOver centre
Ear, frogs and crossings, commercially available from Mark Hughes.Use Commercial items.Various
Trolley pole commercially available from KW Trams.Use Commercial items.Various
Trolley wheel (actually fitted as non rotating, operating as a skid) commercially available from KW TramsUse Commercial items.Various
Trolley skidUse Commercial items.Various

NOTES

TRACK

The recommended track is either Code 75 solid nickel silver, flat bottomed. Flexible track, points and crossings of both these types are produced by Peco (called 'HOm') and are recommended.

WHEELS

The width of tramcar wheels are much less than railway wheels, with a smaller flange and flange depth. However, in 'TT' gauge to use exact scale wheels would require very precise track construction and wheel setting. To get reliable running, most modellers use normal 12mm gauge commercially available wheels and track, that is to the rather coarse scale railway standards. Although the wheels and groove are much wider, visually it is acceptable. In 'TT' gauge it is usual for modellers to use the most suitable motorised chassis available. For example the Halling 'HOm' motorised chassis for bogie and four wheel cars.

OVERHEAD

There are no ready made traction poles available commercially. So make your own from 3mm diameter brass or steel rod. The poles should allow an extra 15mm at the base for fixing to the baseboard. Holes should be drilled in the baseboard to give a push fit for the poles. In "Distance apart of traction poles on straight track" we recommend that the poles are closer than prototype, as this increases the apparent length of small layouts and makes them look more realistic and interesting.

Overhead ears and frogs in 'OO' gauge are made by Mark Hughes. Though slightly too large they are visually acceptable for 'TT' gauge.

Working trolley poles will need to be scratchbuilt, though parts from commercially available 'OO' gauge poles can help. These are made by KW Trams. Many 'TT' gauge tramway layouts have overhead wiring but dummy trolley poles.

Pantographs used by tramway modellers are always commercially available items from the model railway field. It is not worthwhile trying to scratch build this item.

POWER SUPPLY

The standard power supply is 12 volts DC, using model railway controllers. The recommended controller is the electronic feedback type and the handheld (HH) from Gaugemaster has been used with great success. It requires a separate 16 volt AC supply from a transformer (also available from Gaugemaster). The controller is very small and can be carried around the layout with ease.

There are two main styles of operating trams in "OO" scale. Using two rail supply, just like the model railways, or, more properly, using a live overhead system. Here the power is fed through the overhead and returns via the rails, just like the prototype. However, there is one major difference between model and the real thing. In the model the overhead is one continuous electrical supply. All sectioning is done through the track. This makes modelling much easier and prevents stalling on overhead dead spots.

LINKS FOR WHERE TO GET EVERYTHING

List of TLRS standards for other scales.



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