A motor driving the newly built escalators at Metro's Dupont Circle station failed, raising broader concerns about similar equipment being used elsewhere in the transit system.

Metro reopened the 19th Street entrance of the Dupont Circle station in October, after about nine months of construction to replace problematic escalators there with all new equipment. But within weeks of reopening, Metro had one of the new escalator motors "burn up," Rob Troup, Metro's assistant general manager of transit infrastructure and engineering services, told board members this month. The failure was among 20 outages within the first 40 days after the heralded entrance reopening.

It's unclear what caused the Dupont Circle escalator motor to fail. "Analysis by the original equipment manufacturer will determine exactly what happened," said Metro spokesman Philip Stewart.

But the motor failure prompted the manufacturer to swap out a similar new motor at the Foggy Bottom station earlier this month to inspect it, said Metro spokeswoman Caroline Lukas. The motor was pulled during nonpeak hours and took only one of three Foggy Bottom escalators out of service, but the Foggy Bottom motor had not failed.

"As a follow up to Dupont Circle's motor replacement, the manufacturer wanted to perform this analysis preemptively," Lukas said.

The Foggy Bottom equipment is only about a year old. Metro replaced all three of Foggy Bottom's exit escalators last year, the first replacement of escalators in the system in more than a decade. Metro touted it as the start of a major escalator improvement plan to replace 94 of its 588 escalators over seven years.

The motors are covered by warranties, though, meaning Metro does not have to pay for the work.

Agency officials have said the new escalators are higher-tech "transit grade" models that meet American Public Transportation Association standards and are more robust than the equipment they are replacing. But the new equipment does bring some other side effects that can translate to stalled escalators for Metro riders.

The new escalators have what Troup called "a higher level of safety device" that can cause an escalator to shut down more easily. That has caused multiple outages when a heavy suitcase hits a stair or other safety warnings are triggered, causing the whole escalator to shut off.