The Storage Battery as Applied to Electric Railways.
B'ยข W. E. WINSHIP.
Within the last few years there has been a decided change in the attitude generally taken as to the advantages and advisability of storage-battery installations. This is partly due to a better knowledge of the life which may reasonably be expected, and, to a minor extent, to improvements in construction and plates.
Storage batteries have shown their utility and economy especially in railway work, where current fluctuations are usually extreme.
Where the system, Supplied from a single station, is large, and relatively small cars are operated, the instantaneous fluctuations will be a small percentage of the total load, and there would be no economy gained in removing them. The load in this case will very nearly follow the service supplied ; i. e., be steady and proportional to the number of cars, and the only effectual use of a storage-battery plant, outside the large element of reliability of operation secured by it, would be in regulating the load-factor on the generating units in service. There would probably be, even in this case, a considerable economy resulting in operating the generating units and boilers at their most efficient load. This fact and their importance as a reliability factor might determine their installation under the above conditions.
When large cars are operated, perhaps even in trains, and high accelerations are demanded, as in interurban work, the conditions are entirely different. The fluctuations are then enormous, frequently much in excess of ioo per cent. over the average load, and we very often find stations operating on a 50 per cent. load-factor in order that the maximum demand may be within the overload capacity of the generators.