The escalators at the 16th Street BART station have gone bust again, but this time human excrement isn’t to blame for the 36 days and counting that the stairs have been stilled.

Old age was the culprit, according to an email from Robert Cotton, BART’s power and mechanical section manager. The 40-something-year-old gearbox had leaky seals and was laid to rest on August 27.

The escalator is scheduled to be resurrected on October 4.

Like a transmission in a car — only bigger — the gearbox sits next to the motor under the “hood” of the escalator, where it controls the movement of gears with chains looped around them.

The motor turns the gears, which rotates the chains that in turn make the steps go round. And, similar to the transmission fluid needed to make a car switch gears, escalator gearboxes have seals and gaskets containing fluids that lubricate the gears to move the chains. Over time, leaky gearbox seals may destroy the gears, ultimately shutting down all movement.

How an escalator works. Diagram by  Electrical Know-How

The components of an escalator. Diagram by Electrical Know-How

Lindsey Pettis, station agent of eight years who is one of the first to put in requests for maintenance, says escalator shutdowns that frequently plague BART can often be fixed in 30 minutes.

Repairing gearboxes is a whole different story, according to Cotton. “Removing [gearboxes] is very difficult, and then the actual repair has to be done in a certain way. Setting up gears is a precise effort.”

Getting parts added to the delay. Cotton and his team have been waiting on rush-ordered parts and some special orders, which can take up to 10 weeks.

In the meantime, Pettis will continue to be a daily sounding board as people shout out their escalator woes when darting towards the platform stairs, or take a moment to personally discuss the issue with him and file a complaint via BART’s comment cards that his supervisor picks up daily.

“In the morning, when people are rushing to work and the escalator is out, that’s when we get tons of complaints,” Pettis says.