Abstract :
The automatic substation is defined, and its history is traced from the first station placed in service in 1914 to the present time. The number of automatically controlled railway stations up to the beginning of 1922 is given as 142 equipments totaling 86,000 kw. Outside the city of Cleveland, two-unit stations have been installed in but four instances, although a number of these stations are now under construction. With manually operated stations, especially in interurban work, the location of stations is determined by local conditions, availability of labor, etc. rather than by load conditions. But with the advent of the automatic substation it is possible to locate stations more nearly at the proper points to take care of the system loads giving improved voltage conditions with a minimum of feeder copper. Accessory advantages, in addition to the labor saving item, include a reduction in running light losses, a reduction in distribution losses, lower cost of substation and, in some cases, an actual retirement of existing feeder copper. An example is cited of a double track line 80 miles long with figures from a report which shows a net annual return on the investment, including 6 per cent interest, of 34.9 per cent. The labor saving is based on two twelve-hour shifts, and it is further calculated that with three eight-hour shifts the annual saving would be increased by an appreciable figure.
