SCADA Systems in Railways Vulnerable to Attack Government officials initially believed railway signal disruptions in December were tied to a cyber-attack against a Northwest rail company in December, Nextgov reported. But government and railway officials later denied that a U.S. railroad had actually been hit by a cyber-attack. "There was no targeted computer-based attack on a railroad," said Holly Arthur, a spokeswoman for the Association of American Railroads. While an attack has been ruled out, the incident highlights the dangers of industrial control systems controlling critical infrastructure. Train service on the unnamed railway was "slowed for a short while" and schedules delayed for 15 minutes on Dec. 1, according to a Transportation Security Administration memo obtained by Nextgov. A "second event" occurred just before rush hour the next day, but it did not affect schedules, according to the Dec. 20 memo, which summarized the agency's outreach efforts to share threat intelligence with the transportation sector. "Amtrak and the freight rails needed to have context regarding their information technical centers," the memo said, adding that rail operators were not focused on cyber-threats.