The modern demands of industry for speed and large capacity have called
for strengths exceeding that possible to attain from hemp or manila
ropes, which are not excessive in size or cost. As a result, steel
ropes and cables have been developed and perfected to a high degree of
strength and dependability. The majority of hoists and cranes use steel
rope. Logging industries depend for most part on steel cables. Cable
cars use special steel cables which in many cases are several miles
long. Long tramways use light steel cables, for long spans where manila
rope would scarcely maintain its own weight. High speed passenger
elevators maintain safe and dependable service day after day only
through the strength of the perfected flexible steel cable. However, as
stated above, each particular type of service calls for some special
type of cable. The following tables are not complete but will serve to
indicate the scope of the field covered by this subject.