GRAND CENTRAL'S CLANDESTINE SUBSTATION
A couple of years ago NYC URBANISM gained access to the clandestine basement substation, thirteen levels under Grand Central Terminal, which is off-limits to the public and not listed on any blueprints or maps. Grand Central’s best-kept secret, its very existence was only acknowledged in the late 1980s.
Known as M42, the substation is supposedly the lowest elevation of any space in the city, only accessible by a long staircase that travels through layers of Manhattan schist bedrock or an old Otis elevator. When it was built in 1930 it was the largest substation in the world, equal in size to the main concourse above. The 22,000 square foot room held nine massive rotary converters, converting 11,000 volts of AC to DC to power the third-rail on 2,000 miles of track. In the late 80s, the converters were replaced by modern 3,300-kW solid-state traction rectifier units, however, two of the original converters are still located in the substation, relics of the terminal’s historic past.
M42 played an important – albeit largely unknown – role in World War II. During the war, the room was so secret that armed guards were stationed at the entrance with orders to shoot anyone without proper clearance on site. But someone who worked in the room notified Hitler of its contents. Nazi spies targeted the substation, devising a scheme to halt the movement of 80% of the equipment and troops in the Northeast, who used the rail network to transport around the region. The plan was to sabotage the substation, shutting off power to all the trains by dumping sand into the rotary converters, causing them to short circuit. The Nazi’s sent their spies on U-boats to the coast of Long Island in 1944, landing in the middle of the night. The spies were spotted by the Coast Guard who warned authorities before losing them in the fog. But the FBI was on high alert for the Nazi spies, who made one fatal mistake. When they arrived at Grand Central they checked their luggage, and the FBI had been searching all the checked bags. When the spies returned later that day to retrieve their bags, they were arrested and two were eventually executed.