There was no explosion or emergency at the Smithsonian station today, according to Metro, but an object’s contact with the third rail did cause a spark and boom.

Trains are now single tracking between the Smithsonian and Federal Center SW station. Delays are expected.

The Metropolitan Police Department and Fire and EMS both responded to a report of an explosion this afternoon at the station. “Further investigation revealed a transformer in the Metro station had failed, causing some smoke and shutting down one rail,” Sgt. Mike Architzel of First District said in an email to a listserv. “No injuries were reported and after an inspection by the Fire Department, the station was placed back in service, operating on one rail.”

Metro says a “cover on the third rail made contact with the energized third rail itself.” No injuries were reported.

Just came running out of @wmata station at smithsonian – sparks/loud bang/ smoke – we all went running out

— Steve Spaulding (@SpauldingCC) July 10, 2014

Some type of explosion on @wmata at @smithsonian station. pic.twitter.com/66EecvLk2E

— Seth Statler (@SethStatler) July 10, 2014

@unsuckdcmetro Smithsonian delay with sparks and fire train holding could be circuit breaker. Mechanical problems pic.twitter.com/ue2iWYGxSJ

— Steven N. Geiger (@GeigerSteven) July 10, 2014