16-ton train without the aid of a stationary steam engine. It became apparent that the
cumbersome inclined planes that slowed traffic were not necessary and that the theory of railway
location needed revision. As a result, a series of longer, more gradual ups and downs, known as
developments, replaced the short steep cog grades or inclined planes. Although routes were
longer, as illustrated in figure 1.1, time and money were saved.
Figure 1.1. Gravity and Development Lines.
The successful experiment of the "George Washington" made a permanent change
in the theory of railway location. It was a turning point in railway progress.
The path a railroad follows is known as its horizontal alinement or simply alinement. It
may be defined as the ground plan of the railroad as distinguished from its profile. In a profile,
you see the ups and downs of the railroad's path. But on the ground plan you see stretches of
straight track, connected by arcs or curves. The