Gauge 0 was the most popular size pre World War 2. Track gauge is quoted as 1-1/4” or 32mm; or in continental Europe, 35mm because they measured between rail centre-lines.
The scale is 7mm/foot or 1:43 in the UK, 1:45 in continental Europe and 1/4”/foot or 1/48 in the USA. However, tinplate toy trains rarely adhered to a strict scale!
Motive power could be steam, clockwork or electricity. Some early electric sets operated from the mains supply with an arrangement of lamps and resistors to reduce voltage. In part, this was because power supply had not been standardized and some power companies supplied DC (direct current) which could not be isolated by a transformer. This was a potentially lethal arrangement and was quickly superseded. The predominant standard became 18 or 20 volts AC (alternating current) for the toy market. Track was invariably made with a rather unrealistic insulated centre-rail to provide current. Motors were ‘wound field’ and would run on DC too, but reversing presented a challenge. Generally it meant a switch on the loco. Hornby offered locos that sensed an abrupt application of full voltage to reverse the field winding. Lionel had something similar. Zeuke and Distler in Germany had ingenious and better solutions which make interesting reading.
Manufacturers of finer scale trains (Bassett-Lowke, Leeds Model Company etc.) benefitted from the better permanent- magnet motors after the war and adopted 12v DC. Some systems (Fleischmann of Germany, Penzverde of Hungary) stayed with AC but took advantage of the better insulating materials now available and went two-rail.
Tinplate trains were sometimes enamelled but the most attractive were tinprinted. Sadly, these are near-impossible to restore because, once scratched, the print is ruined. Some makers used printed paper wraps (‘lithos’) around wooden carcases at some point in their history. Leeds Model Company in particular persevered with this method, achieving very passable results.
The last to grow up with 0-gauge toy trains were the post-war ‘baby boomers’ and when they reached maturity and retirement it caused a resurgence of interest and the emergence of modern makes like ACE, Darstaed and the reborn Bassett-Lowke. Much is sourced from the Far East and Eastern Europe.
In our little ‘cottage industry’ we strive to provide goods made in the U.K.