We [in the USSR] got a computer sabotage by the United States of America. It was a gas leak in the gas pipeline, and two trains that drove into this cloud burned completely. Two passenger trains. And it was only in the late 90s that we learned from the memoirs of the CIA agents that it turned out to be a CIA mission. That they inserted computer bugs, which conducted the corresponding sabotage.
Mixing up two different stories. Thomas C. Reed, a former Air Force secretary, writes in his book "At the Abyss" that a C.I.A. campaign of computer sabotage resulted in a huge explosion in Siberia in 1982, with no casualties known. www.nytimes.com/2004/02/02/opinion/the-farewell-dossier.html, The claim has not been corroborated by intelligence agencies in the United States
The largest railway tragedy in the USSR after WWII occurred on June 4, 1989 as a result of a volumetric explosion of the gas cloud formed by the gas leakage from the pipeline "Siberia - Ural - Povolzhie", when two passenger trains were passing by about 1 km from the place of it. 645 people were killed, more than 600 injured. Officials reported about the explosion power of 250-300 tons of trinitrotoluene. Independent experts believed that it was 12 kilotons of TNT, which is comparable to the nuclear explosion in Hiroshima https://www.springer.com/us/book/9783319242996 . According to the official investigators, a gas leak from the pipeline happened due to damage caused by the excavator bucket during its construction in October 1985, four years before the disaster. The leak started 40 minutes before the explosion.