"by Greg Moore » Mon Aug 26, 2019 2:00 pm"
I wish there was a 'like' button. Having worked in telecom, I can state that there are many things, some obvious and some not, that an adversary or potential
adversary can implant in such systems. It need not do anything dramatic; how about simply having trains go into a fault mode which requires them to limp at 10 kph to the yard, where an intermittent, time-eating, rabbit chasing problem appears? A train doing that in Boston disrupts an entire line, as they have no express tracks and few mid-line pull-out yards. It doesn't take much creativity to invent a dozen sleeping adverse capabilities one can implant in a device as complex as a modern subway car.
Consider the time that the US ambassador to the USSR, Averell Harriman, accepted a gift from the USSR, a perfectly carved wooden replica of the Great Seal of the USA. After receiving it as a 'gesture of friendship', the clueless rich twit hung it on a wall in his Ambassador's residence (in Russia), in an office where he discussed confidential business. Our ally from WWII wouldn't dare spy on us, would they? How could a piece of wood be a spy device? Thus was it placed exactly where the Soviets wanted.
It was, of course, a listening device, only not of the type rich twits understand. It used an early version of an RFID transmitter, so it required no batter and transmitted no signal until activated. The device was eventually discovered. By accident. In business between adversarial nations, anything you don't understand is almost certainly not working in your favor, and anything from an adversary which is integrated into your daily life is probably doing something you don't understand.
http://mentalfloss.com/article/584493/s ... even-years