Comparison of common scales and gauges

All dimensions in decimal inches
Examples taken from German rolling stock

Gauge Scale Track
gauge
to scale
min. radius
industrial
min. radius
Length
Class 01
Length
Class 89
Length
4-axle coach

Length
2-axle freight
Height
clearance*
  1/1 56.5000 7086.6100   940.9400 346.4600 1039.3700 366.1400 236.2200
1 1/32 1.7700 220.4700 23.62000 29.4100 10.7900 32.4800 11.4600 7.0900
0 1/45 1.2500 157.4800 27.56000 20.9100 7.6800 23.1100 8.1500 5.0000
H0 1/87 0.6490 82.6770 13.77900 10.9450 3.9760 11.9290 4.2120 2.7160
TT 1/120 0.4724 59.0550 11.22050 7.8350 2.8740 8.6610 3.0700 2.0470
N 1/160 0.3543 43.3070 7.67700 5.8661 2.1653 6.4960 2.2830 1.5354
Z 1/220 0.2559 33.4645 5.70866 4.2913 1.5748 4.7244 1.6535 1.1024

* These dimensions are based on European models. Add about 1/2" for American models.