Thursday night, after the National Weather Service issued a flash flood watch for the city, Elliot G. Sander, the authority’s chief executive, announced that officials were rechecking storm drains, placing pumps at all of the system’s “flood-prone” locations, calling in additional signal, ventilation and drain maintenance workers, readying buses to ferry stranded passengers, and delaying all but the most urgent construction.

As for improving communication, managers and other employees were to be dispatched to the busiest stations. Some were given bullhorns.

Of course, the scale of New York’s subways, which deliver 4.9 million rides each weekday, dwarfs any other system in the country, making it much harder — and more expensive — for the authority to maintain and improve its communications system. On Wednesday, the authority’s Web site, one of the busiest in the country, was updated frequently and received a record 44 million hits. (A hit is a request for a single file on a Web server.)

However, untold numbers of people had trouble getting through to the site. The firewall software that screens users on the network could not handle the surge in traffic, so technicians tried to free up capacity by asking employees to limit their online activities and by disabling bandwidth-consuming functions, like videos of old board meetings, on its Web site.

“To say the Web site was down is not correct,” said Christopher P. Boylan, a deputy executive director of the authority. “It was just at its maximum capacity.”

That distinction did little to help Richard Cattafesta, 46, an advertising executive who lives in Windsor Terrace, Brooklyn, and who gave up waiting for a bus on Wednesday morning after several passed him by. He went home, thinking he could get an update online.

“I got on the Web and got to the M.T.A. site, but I could not download any information,” he said. “I clicked ‘reload’ again and again. I finally got a partial download, but I got no service information whatsoever — just the banner of the site.”