CITYWIDE -- AN EXPLOSION IN AN ELECTRICAL SUBSTATION IN BROOKLYN is being blamed for a massive power outage on the F line that left 3,500 riders stuck in tunnels for several hours during the Wednesday, Dec. 11 evening rush hour, reported Gothamist on Thursday. An explosion blew a door off its hinges in an electric room that MTA officials said is located in Brooklyn and that powers several New York City subway lines. The Brooklyn Eagle reported on Wednesday that riders had to be evacuated from two F trains that were between the Hoyt-Schermerhorn and Jay Street/MetroTech stations when the third rail lost power. But the problem turned out to be more widespread, affecting other subway lines as well. Evacuations from the aforementioned F trains took almost three hours. Speaking at a news conference on Thursday morning, MTA chair Janno Lieber said the electrical station was 90 years old. "That speaks to the urgency of making the investments to the very old pieces of our system."