Code 83

[rogertra]

British OO models are 4mm to the foot.

That's not the same thing.

[JerryB]

British OO models are 4mm to the foot.

The assertion about 4mm scale above seems to be deliberately trying to confuse the folks asking questions here. Lots of scale factors are described in various measurement units for a variety of (usually historic) factors.

That has absolutely nothing to do with crossing two measurement systems as was done above in claiming that 'code' is somehow a combination of inch and metric specifications. It isn't.

In track and rail, the code numbers simply specify the height of the rail in thousands of an inch, that being an American inch. Here are some examples:

• Code 332 rail is 0.332" tall
• Code 250 rail is 0.250" tall
• Code 100 rail is 0.100" tall
• Code 70 rail is 0.070" tall
• Code 83 rail is 0.083" tall

There is no metric term associated with the specification of rail height using the code numbers.

Happy RRing,

Jerry