Consequently, the wheel diameter was small at 68 inches (1727 mm).

Over a period of time, the wheel diameter reduces up to 819 mm.

They correspond to wheel diameter of 899-864, 862-840, 839-820 and 819 mm.

The coupled wheel diameter was increased from 1,006 to 1,100 mm.

The last number is the wheel diameter in inches.

The wheel diameter is effectively the "gear ratio" of a steam engine.

Because of its large wheel diameter, it could also be used to haul passenger trains.

This increases the wheel diameter and the curve can be taken more easily.

These decisions appear to have been taken at quite a late stage, since the cylinders were cast to suit the larger wheel diameter.

The wheel diameters are increased to 17" in size.