A historic or British term for a coin-sized explosive device strapped to the top of a rail. When a locomotive wheel crushes it, it detonates with a loud bang to alert the engineer to stop or slow down immediately. In North American railroading, this device is universally called a torpedo.
Heard on the job
You better lay down a couple of fog signals if you're going to be fouling the main in this soup.
Also heard as
- torpedo
- detonator