What’s the best way to plug a giant hole? Why with a giant plug, of course. That’s the thinking of the Department of Homeland Security’s (DHS) Science and Technology Directorate (S&T), which has created just such a giant plug to contain flooding or dangerous gases in mass transit tunnels. Measuring roughly 32 feet (9.7 m) long and with a diameter of 16 feet (4.9 m), the giant plug is an enormous inflatable cylinder that can be filled with air or water in minutes to quickly seal off a section of tunnel in the event of an accident, natural disaster or terrorist attack.
Read the full article: Giant plug for sealing off subway tunnels in a hurry