From the file's introduction
A garbled, static-filled transmission in a foreign language emanates from a radio’s speakers and tells the heroes to stop a vehicle from crossing a certain set of railroad tracks. But where does this transmission come from, and why can’t anyone else hear it?
Faint Transmissions is an adventure that finds the heroes, wherever they may be. It is best used as a brief interlude between regular adventures in the campaign. The scenario outlines a task and describes those who oppose its completion. In addition, information is given about what “punishments” are levied against heroes who elect not to undertake the task at all.
A Short d20 Modern Adventure for Four 2nd-Level Characters