Detonator (railway)

Torpedoes are essentially obsolete in the U.S. as soundproof construction of modern locomotive cabs renders them useless.

Quoting from the terminology book of the Brotherhood of Railroad Signalmen: A torpedo is a device which is strapped to the top of a rail.

The torpedo was invented about 1874.If a train unexpectedly explodes a detonator, the driver is required to stop immediately and investigate.

Only the ICE 3 trains and other locomotives that travel to France still have detonators on board, because of French regulations.

In November 2010, the Taiwan Railway Administration deployed 800 detonators for destruction on maintenance tracks.

According to Military and Civilian Pyrotechnics by Ellern, page 376, FORMULA 155 – Railroad Torpedo, is by mass:[9] The length of Garratt locomotives made the sound of a detonator hard to hear, so New South Wales 60 class locomotive had "sound pipes" to bring the noise of the explosion to the crew.

This illustration from an 1882 Leslie's Monthly portrays an engineer (fireman) finding a torpedo on the track.
A torpedo on a rail
A detonator on a railway line in Belgium
South African example
Engineering staff working inside a possession, seen from a train passing on an active running line.