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H0 Gauge Standards |
| SCALE/GAUGE NAME | H0 Gauge | Prototype |
|---|---|---|
| SCALE | 1:87 | 1:1 |
| TRACK | ||
| Standard track gauge | 16.5mm | 1435mm |
| Rail profile | Code 75 | Grooved girder |
| Groove width, straight track | 1.25mm | 32mm |
| Groove width, curved track | 1.5mm | 38mm |
| Minimum radius curve, older trams | 140mm | 15 metres |
| Minimum radius curve, modern trams and large bogie cars | 180mm | 20 metres |
| Double track distance apart (track centre lines) | 45mm | 4 metres |
| WHEELS | ||
| Recommended to "OO" gauge BRMSB standards (ie Jackson, Romford or Tenshodo). | BRMSB | ------ |
| Back to back | 14.5mm | ------ |
| Axle diameter | 2mm | ------ |
| OVERHEAD | ||
| Minimum height above road | 70mm | 5.8 metres |
| Wire type and diameter | Nickel silver 0.3mm | Copper 8mm |
| Length of traction pole above ground | 96mm | 7620mm |
| Distance apart of traction poles on straight track | 150mm average | 36 metres(maximum) |
| 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 |
| 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). | Use Commercial items. | Various |
| Trolley skid | Use Commercial items. | Various |
NOTES
It is generally accepted that modellers using "HO" standards are modelling Continental or American systems. British models are usually built to "OO" tramway standards
TRACK
The recommended track is Code 75 solid nickel silver, flat bottomed. Flexible track of this type is produced by Peco and is recommended. SMP produce tramway points using code 75 rail as either ready made items or in kit form. The standard 'HO' gauge roller gauge has the check rail gauge set to give a 1.25mm gap with the running rail. This can be handy when constructing track. Details on track construction, overhead and tramway modelling in general is given in "How to Go Tram and Tramway Modelling" by David Voice.
WHEELS
The width of tramcar wheels are much less than railway wheels, with a smaller flange and flange depth. In 'HO' gauge to use exact scale wheels would require very precise track construction and wheel setting. To get reliable running, most modellers use commercially available wheels and track, that is to fine scale railway standards. Although the wheels and groove are much wider, visually it is acceptable. Similarly the diameter of tram wheels is generally smaller than railway wheels. In 'HO' gauge there are three main wheel diameters; 10.5mm, 9mm and 7mm. The 10.5mm are the larger diameter wheels found on most four wheel trams and older bogie trams. The 9mm diameter are found on modern low height four wheel trams, equal wheel bogies and the driving wheel for maximum traction bogies. 7mm are found as the pony wheel for maximum traction bogies and on some very modern low floor trams. All three diameters are commercially available under the Romford name. Modellers often use 9mm wheels to give more clearance and to allow for the over scale flanges.
OVERHEAD
Ready made 'HO' traction poles are produced by Sommerfeldt. They are strongly made in steel to the correct standards. They have a length of pole at the base for fixing to the baseboard. It is recommended that you keep the overhead as close as possible to the 70mm above rail top height. So take care when placing poles on the pavement. This can lift the overhead by as much as 10mm and cars with short bows may not reach it. 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.
Suitable overhead ears and frogs are made by Mark Hughes. These can be fixed to span wires bracket arm poles. Hard drawn nickel silver wire 0.3mm diameter (or 33swg) is available from Eileen's Emporium. This is soldered to the ears.
Workng trolley poles in kit form are available from KW Trams.
Working bows are available ready made from Sommerfeldt .
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. The types from Sommerfeldt are recommended.
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 'HO' 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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