Abstract
THE motive power on our great railways forms such an that any important question that any enterprise made with a new or otherwise, adapted so as to utilise the existing rolling-stock, not only may at some future time greatly accelerate the present speed, but also introduce great economies, especially if the new power can be derived from a natural source. In Italy the railway authorities have been thoroughly alive to this fact; a portion of the railway of northern Italy has been electrically equipped for running by means of electric motors, as a pioneer installation, and if successful the remainder will be similarly equipped. The Valtellina electric railway (says Feilden's Magazine for January), which is sixty-two miles long, runs from Lecco along the shores of Lake Como to Colico, where it divides, one branch going to Sondrio and the other to Chiavenna. The power of the line is furnished by falling water from the river Edda, which operates four turbines (2000 h. p. each) and which, coupled direct with four Schubert three-phase generators, give a current at 20,000 volts and 15 cycles. This current is led to ten substations (placed about six miles apart) along the route, where it is transformed to 3000 volts, at which voltage the various sections of the line are ted. The two overhead trolley wires which supply the motors (the railway track forming the third) are hung from steel wires supported on each side by posts spread with crossbeams; these also carry the main supply wires (20,000 volts). The traffic of the line comprises both goods and passenger, and it is worthy of note that for the former electric locomotives are used for the haulage of the wagons (which are of the standard Italian type), and for the passenger traffic bogie motor-cars act in place of locomotives and pull four coaches as trailers (these latter also of the ordinary Italian type). A train of this description is run at thirty-nine miles per hour on all gradients less than 10 per cent.; for anything steeper than this “the Cascade” arrangement of motors is used, then the speed is halved. The speed of the goods traffic is twenty miles per hour with a load of 250 tons. The line is equipped with every facility for safe working, everything being made as automatic as possible. For instance,“when a train receives a block signal it also has its current cut off so that it cannot proceed.” Again, “where a train is coming up at full speed, and it is necessary to order it to stop owing to sudden occurrence of something in front, the signalman not only makes the signal to stop, but he also cuts off the current and applies the full brake power available to the advancing train.” Lightning has been fully guarded against. The power house is supplied with a group of conductors of the “Horn ” type outside the building, and lightning arresters of a similar type are fitted in the substations, and, lastly, the electric locomotives and motor-cars have also similar apparatus fitted. The working of the line will not only be watched with interest, but also forms an important example of electric traction on account of its newness in design (especially in detail), and the thorough way in which the system is made automatic and interlocking and also safely guarded against accidents.
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An Italian Electric Railway . Nature 65, 308 (1902). https://doi.org/10.1038/065308a0
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DOI: https://doi.org/10.1038/065308a0