The system was removed from service June 8th 1976. I guess it was perfect timing that I came across the department order and this thread was started.
D.O. 95 June 11th 1976.
Coney Island High Pressure Pumping Station has been removed from service June 8 1976. High pressure system will now function as a distribution system, supplying hydrants on the system via three inter-connections with the regular trunk main distribution system. Residual pressure is estimated at 75 to 95 psi, with an increase in gallons flow for firefighting purposes.
Operations from hydrants on the system are to be conducted in accord with evolutions for low pressure hydrant operations, since the system is now a distribution system.
All existing instructions relative to increase/shut down of Coney Island pumping station etc... are suspended pending regulation revisions.