According to Nextgov, a government memo reveals that hackers disrupted signals at an undisclosed railway company in December of last year.

"According to the memo, train service on the unnamed railroad located in the Pacific Northwest 'was slowed for a short while' on Dec. 1, and rail schedules were delayed about 15 minutes after the interference," writes Wired's Kim Zetter. "The next day, shortly before rush hour, a 'second event occurred,' but this one did not affect schedules, NextGov reports."

"An investigation determined that hackers -- possibly from overseas -- had penetrated the system from three IP addresses, according to the memo, which did not name the country from which the hack occurred," Zetter writes. "'Some of the possible causes lead to consideration of an overseas cyberattack,' the memo said."

Go to "Hackers Breached Railway Network, Disrupted Service" to read the details.

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