Underground duct leading from E core to the Boiler House. This is the E core end. The duct carried heating, and domestic hot water (ie what comes out of taps) pipes and electrical cables. There is also a large gas pipe.
The original plans show chilled water pipes in this duct but either they were never installed or were later removed. I suspect they were never installed due to trying to keep costs down but if they had been installed and the air handling unit in the penthouse had had a cooler battery then this would have supplied conditioned air to the main A-B and A-E core spurs of the WRB!