More than 100 escalators, about one out of four throughout the Metro subway system, are shut down at least for several hours on most days. But only a few of them are broken.

Instead, Metro officials say, many escalators are temporarily immobilized to reduce power consumption, undergo general maintenance, or allow them to be used as two-way staircases. On a typical day, just 17 of the 436 escalators are apt to be out of order, officials said after a recent spot check.

The breakdown rate for escalators has held relatively steady in recent years, said David O. Cooksey, Metro's general maintenance director, and accidents have decreased.

A recent incident in which a 3-year-old girl died after a drawstring attached to her jacket hood became caught in an escalator's treads set off renewed debate about the issue. But officials said injuries dropped from 184 in 1982 to 158 last year, mainly because of a reduction in escalator speeds.

All the same, passengers repeatedly encounter stopped escalators. Among the reasons: The 17 escalators that break down on an average day -- officials said the day-to-day total may range from 4 to 40 -- are widely scattered throughout Metro's 57 subway stations. So many riders may see at least one that needs to be fixed. Another 14 escalators are likely to be down for routine maintenance. Officials said this normally is not done during rush hours. Eighty-one escalators are shut down -- either permanently or from two to 14 1/2 hours a day -- at nearly 40 stations to reduce electric costs or permit two-way use. For example, officials said, one out of three escalators may be halted at a crowded station if the number of passengers going up is about the same as going down. It may then be used in both directions.

Why do escalators break down? Cooksey and other officials said the causes range from short circuits and worn-out brake mechanisms to broken hand rails, flooded pits, and coins jammed in treads. Short, indoor escalators are as susceptible to malfunctions as long outdoor ones, they said.