>>1623640Omitting large scales and weird inventions, there are:
H0 1/87 - most common and most playable one
TT 1/120 - mostly used in former socialist countries, but also in USA and New Zealand
N 1/160 - second most common, but feels small
Z 1/220 - really small, but stil playable
Analog aka DC - trains are controlled by DC voltage put onto the tracks. Cheaper, but requires quite a lot of wiring.
DCC - trains are controlled by magic box (command station), wiring boils down to two wires - one for each rail. Gives a lot of possibilities, pararell operation, etc, etc.