At 6:14 p.m., on Friday, Nov. 1, 1918, hundreds of weary New Yorkers boarded a Brooklyn Rapid Transit train at Park Row in Lower Manhattan for the ride home to Brooklyn.

Some would have to return to work on Saturday morning, but the rest had endured another workweek, and all of them had survived the deadliest month of the influenza pandemic. Each day, reports from the war in Europe seemed more promising, too, but war news still filled that morning’s New York Times front page, except for some small ads at the bottom.

At least one of them vaguely augured what would dominate the next day’s news:

The makers of Calox tooth powder were offering customers a free guide to the city’s subway system, which was undergoing an expansion that, among public works projects, rivaled the recently-opened Panama Canal.

As it is today, so it was 100 years ago: Subways would continue to operate during construction work. When a train left Park Row, the terminal across from City Hall, the following afternoon, it was still twilight thanks to Daylight Saving Time, imposed for the duration of the war. But when the 30-year-old wooden cars rumbled across Brooklyn Bridge, over the Fulton Street El and finally descended into the open cut adjoining Prospect Park, there was nothing but pitch blackness; the car in the front did not have headlights to illuminate the tunnel ahead.