I was employed as a tower man at Dover third trick from 1970 to 1974. Dover still had the arm strong levers but the plant was electric powered switches. There were two traffic levers governing reversible traffic between Dover and Denville, tracks 1 and 2. I was also qualified at Denville, Port Morris, Suffern. With the advent of ConRail I transferred to train service, retired 10 years ago from NJ Transit, 43 years of railroad service. Nice explanation.
WRT the question at 20:43 regarding electrical interlocking and loss of power. From my research on interlockings in the 1920s. Electrical interlockings were not getting primary power from the electric grid. First because in the 1920s the grid as we know it today didn't really exist. There were limited grids near major cities, but throughout the countryside, not so much. Second, because interlocking by design have to fail safe, they were usually powered by large battery banks usually located on the first floor of the tower. Batteries were a well understood technology by the 20s and the design rules for operating electrical towers were well defined. There were good rules for estimating the energy required to operate an interlocking. Calculating the power took into account the number of devices that needed to be operated, the number of operations per day, and an arbitrary percentage to be added. The engineer would then add a second bank to the system. These banks would be operated independently of each other. So during a two week period bank a would operate on say even numbered days and bank b would be operated on odd number days. The bank that was not running the system would be available for maintenance of the battery, changing cells, charging the bank, topping off the electrolyte, etc. Don't forget that at this time the track circuits were for the most part battery operated as well with battery vaults along the mainline to provide power to the line relays and signals.
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I was employed as a tower man at Dover third trick from 1970 to 1974. Dover still had the arm strong levers but the plant was electric powered switches. There were two traffic levers governing reversible traffic between Dover and Denville, tracks 1 and 2. I was also qualified at Denville, Port Morris, Suffern. With the advent of ConRail I transferred to train service, retired 10 years ago from NJ Transit, 43 years of railroad service. Nice explanation.
WRT the question at 20:43 regarding electrical interlocking and loss of power. From my research on interlockings in the 1920s. Electrical interlockings were not getting primary power from the electric grid. First because in the 1920s the grid as we know it today didn't really exist. There were limited grids near major cities, but throughout the countryside, not so much. Second, because interlocking by design have to fail safe, they were usually powered by large battery banks usually located on the first floor of the tower. Batteries were a well understood technology by the 20s and the design rules for operating electrical towers were well defined. There were good rules for estimating the energy required to operate an interlocking. Calculating the power took into account the number of devices that needed to be operated, the number of operations per day, and an arbitrary percentage to be added. The engineer would then add a second bank to the system. These banks would be operated independently of each other. So during a two week period bank a would operate on say even numbered days and bank b would be operated on odd number days. The bank that was not running the system would be available for maintenance of the battery, changing cells, charging the bank, topping off the electrolyte, etc.
Don't forget that at this time the track circuits were for the most part battery operated as well with battery vaults along the mainline to provide power to the line relays and signals.