This article was originally published with the title “ Railway Plant—Sleepers, Ties, and Clips ” in Scientific American Magazine Vol. 21 No. 19 (November 1869), p. 292 doi:10.1038 ...

From activating sleeper cells to a possible war, Former Deputy Assistant Secretary of Homeland Security Jack Tomarchio breaks ...

Sleeper cells are spies or terrorists who operate in rival countries and remain inactive until they are essentially ordered ...