With the above wheel arrangement, the leading wheel can be lifted off the ground simply by using your body weight to push the trailing wheel down, and so pass over the obstruction.
32.
The weight borne on the leading wheels was transferred by a system of beams to a hollow cylindrical plunger, which rested on a rubber pad in a cradle immediately above the truck axle.
33.
Each power unit has a single pair of leading wheels in a leading truck, followed by two coupled pairs of driving wheels, with a single pair of trailing wheels in a trailing truck.
34.
These numbers typically represented the number of un-powered leading wheels, followed by the number of driving wheels ( sometimes in several groups ), followed by the number of un-powered trailing wheels.
35.
The 2-8-2 wheel arrangement has a single pair of leading wheels in a leading truck, followed by four coupled pairs of driving wheels and a pair of trailing wheels in a trailing truck.
36.
Thus a Union Pacific Big Boy is a 4-8-8-4; four leading wheels, one group of eight driving wheels, another group of eight driving wheels, and then four trailing wheels.
37.
Under the Whyte notation for the classification of steam locomotives, " " " represents the wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles and no trailing wheels.
38.
Under the Whyte notation for the classification of steam locomotives, " " " represents the wheel arrangement of no leading wheels, ten powered and coupled driving wheels on five axles and no trailing wheels.
39.
Under the Whyte notation for the classification of steam locomotives, " " " represents the wheel arrangement of no leading wheels, eight powered and coupled driving wheels on four axles and no trailing wheels.
40.
Immediately behind the smokebox was a cylindrical sand box; sanding, which was by hand, was provided in front of the leading wheels and behind the rear ones since the engine worked as much backwards as forwards.
