Abstract :
Raillway electrification in Italy dates from 1897, when it was decided to carry out experiments with (1) accumulatortraction, (2) the 650-volt d.c. third-rail system, and (3) the 3000-volt 15-cycle 3-phase system. In 1905 the principal railways were taken over by the State, and between 1910 and 1916 some 230 miles of line were electrified on the 3-phase system at 16¿ cycles. Owing to this system requiring special generating stations, further electrifications have been carried out on the 3-phase system at the industrial frequency (45 cycles) and with 3 000 volts (direct current). The latter system has the advantages of simplicity of the overhead contact line and ease of speed regulation. The policy of further electrification is discussed from an economic standpoint, having inview the large amount of natural hydraulic energy available, whilst all coal has to be imported. A table is given showing the complete operating costs of the whole Italian railway system for both steam and electric traction. The question of regeneration is discussed, this being an important consideration on lines with steep gradients. The equipment of the substations is described, special reference being made to the use of " travelling " substations for both the 3-phase and d.c. systems. Mercury-arc rectifiers are now largely used instead of motor-generators, and are considered to have many advantages over the latter. The various types of locomotives are described in considerable detail, and numerous illustrations of them are given.
