The New Student's Reference Work/Block System

Block System, a system of signals at intervals along a line of railroad, intended to decrease the danger of accident. The system of telegraphing the arrival of a train from station to station, used in England as early as 1839, may be quoted as its origin. It was first introduced into the U. S. in 1876 by the Pennsylvania railroad. In general the block system divides a line into sections, upon each of which only one train is admitted at a time. The system of giving staffs, a staff being given to a train by a station-master only when one has been returned by the train previously upon that section, is a variety of block system which is adapted only to single lines. The serious accidents which occur upon American railroads have led to an agitation for the compulsory use of the block system, which is universal in England but not in America. To keep the sections clear for any one train it adds the additional safeguard of an interval of space to the universal practice of an interval of time between trains. The expense of the block system is sometimes lessened by automatic devices for block signals which minimize the direct manipulation of levers by signalmen.