IN MOSCOW -- The trains get to stop every few minutes. Not the escalators. In a city tied together by its phenomenally jampacked subway system, the escalators here just keep on rolling - morning, noon and half the night.

There are 643 of them in the Moscow Metro. This is a system, like Washington's, with deep, deep stations, but, unlike in Washington, passengers here are rarely left to hoof it on their own up or down immobilized stairways. It wouldn't work, because people don't walk fast enough. At rush hours fully loaded trains run on 90-second intervals; it's up to the escalators to get the passengers delivered, but just as important, to whisk them away again before they start bunching up and spilling off the platforms and onto the tracks.

"In my opinion, they're much more important than trains," says Sergei Likhachev. He would say that, though. He's the chief mechanic of the Moscow Metro's escalator division.

The escalators under his purview carry almost as many people as the trains do - because all but the outermost stations have them - and that can be up to 9 million in a single day. Down. And then up again. Or 2.5 billion a year.

If a train breaks down, he points out reasonably enough, it gets sent to the yard for repairs. No such luck with an escalator. It has to be fixed in place, and it has to be fixed fast.

Without escalators in working order, the Moscow subway system would seize up, and without its subway system, Moscow itself would cease to function. In fact, all of Russia would feel the shock waves, because some unknowably huge number of subway passengers consists of people trying to transfer between train stations or airports in the capital city, the hub of the nation, so they can get from Novosibirsk to Novorossiysk, or from Velikiye Luki to Ust Usinsk, or from Omsk to Tomsk.

In fact Muscovites like to say they never use the Metro anymore, preferring instead to while away the hours topside in endless, epic traffic jams.

Maybe so. But whoever those passengers are, there's an endless river of them, and they ride more than 40 miles' worth of escalators. That's almost a quarter of the length of the rail lines themselves.

How do you keep them running?

"People," Likhachev says. His division has a staff of 3,000. It has workers posted at every station during operating hours. It has a 20-member emergency rapid response team. It also has its own factory churning out spare parts, "so we don't have to rely on suppliers."

This is not to say that all escalators work all the time, because they don't. But let's be clear about one thing: "We do not have escalators out of order," Likhachev says. "We close some for repair."

Likhachev, who is 50, studied in an auto institute, and worked as a technical translator until that job disappeared, and then he tried his hand at car mechanics. But 13 years ago he landed a job with the Metro, on the lowest step of the escalator division, and now he has risen to the top as swiftly as his charges carry their passengers from the depths below to the street above.