increase the lateral strength
increase the vertical stiffness
avoid the stress concentration
reduce the wear
6155 mm2
6615 mm2
7235 mm2
7825 mm2
Broad Gauge
Metre Gauge
Narrow Gauge
both [a] and [b]
450 MPa
500 MPa
700 MPa
850 MPa
61.9 mm
66.7mm
67mm
72.33 mm