Piston effect platforms with a single tunnel, however, air quality worsens when relying on the piston effect alone for ventilation. This still allows for potential energy savings by taking advantage of the piston effect rather than mechanical ventilation where possible. Tunnel boom is a loud boom sometimes generated by high-speed trains when they exit tunnels. These shock waves can disturb nearby residents and damage trains and nearby structures. The perception of this sound by humans is similar to that of a sonic boom from supersonic aircraft, but unlike a sonic boom, tunnel boom is not caused by trains exceeding the speed of
Shock tube detonator Shock tube detonator A shock tube detonator is a non-electric explosive fuze or initiator in the form of small-diameter hollow plastic tubing used to transport an initiating signal to an explosive charge by means of a percussive wave traveling the length of the tube. It was invented by Per Anders Persson of Nitro Nobel AB, patented, and sold by them under the registered trademark Nonel, containing a small quantity of high explosive, but safer and more reliable than detonating cord with the same quantity of explosive. Another early product contained an enclosed combusting, non-detonating fiber. The most common product is