Transit riders traipsed down the stairs, some hauling luggage or grocery bags, while a crew labored over a broken escalator at an entrance to the Powell Street BART Station on a recent morning.

Louise Yokoi of Oakland paused to look at the activity on the escalator and concluded it’s not worth the trouble.

“I see the workmen always fixing the escalators, and it seems to me like a big waste of time and money,” said Yokoi, 50, adding that stairs and elevators alone would be more efficient.

But BART officials are betting that most riders will appreciate an escalator upgrade. Broken and filthy escalators and weeks-long closures often generate complaints. So the agency has kicked off a $96.5 million project to replace 41 escalators at the Embarcadero, Montgomery, Powell and Civic Center stations and add a new one near the Orpheum Theatre over the next six years.

Half a block away from the broken escalator Friday, engineers held measuring tape to another blocked-off moving stairway with its insides exposed at the Ellis and Stockton streets entrance of Powell Station.

The project, funded by voter-approved Measure RR, was prompted by a state of crumbling disarray that has plagued escalators around the city, said Bevan Dufty, president of the BART Board of Directors. Many 40-year-old escalators have been in use twice as long as intended. Constant repairs leave them “held together with paper clips,” he said.

“I think this is really exciting,” Dufty said of the project. “It’s how we welcome or say goodbye to our passengers every day.”

Exposed to the elements, the escalators become rusted and clogged with syringes, human waste and litter. A sign at one repair project told riders it would be completed by “Feb. 30,” he said.

The complaints stacked up.

“It really makes people angry when they start their commute in the morning and they just don’t understand why the escalator’s not working,” Dufty said.

BART also plans to build canopies over street-level entrances to protect the new escalators from the elements. This would be through a separate contract and will cost an additional $50 million to $60 million, Dufty estimated.

The vendor that installs the escalators will also be responsible for repairing them in the first 10 years. BART’s goal is to achieve a 96% reliability rate for the new escalators.

The transit system estimates it can complete six escalators per year. Four escalators, one at each station, will be worked on a time. The first are expected to be delivered for installation next spring.

“I think this is a big step,” Dufty said.

Anna Bauman is a San Francisco Chronicle staff writer. Email: abauman@sfchronicle.com Twitter: @abauman2