UPDATE: L Train Reopens With 'Extensive Delays' Between Brooklyn and Manhattan

WILLIAMSBURG, BROOKLYN — A fire in the underwater tunnel that carries the L train between Brooklyn and Manhattan — the same tunnel in dire need of repairs after being inundated with saltwater during Superstorm Sandy — caused the critical subway line to be shut down completely between the Bedford Avenue station and the 8th Avenue station for the Thursday morning — and afternoon — commute.

The billows of smoke that poured from the tunnel into the Bedford Avenue station Thursday morning were reportedly so thick that a Manhattan-bound L train conductor entering the station couldn't see anything in front of him.

Luckily, no trains were inside the tunnel between Manhattan and Brooklyn when the fire broke out, city officials said, and only one person was injured — a firefighter "transported to the hospital with minor injuries, in serious but stable condition," according to the Fire Department of the City of New York (FDNY).

See also: Brief L Train Shutdown Reveals Dark, Dark Future of the M Train

The L train wasn't so lucky. The line was shut down between Brooklyn and Manhattan for around eight hours Thursday, between approximately 9:30 a.m. and 5:30 p.m., while Metropolitan Transportation Authority (MTA) crews repaired the fire damage.

The Canarsie Tube was reopened to L train traffic around 5:30 p.m., according to an MTA spokesman. However, the L was still running with heavy delays in both directions by 7:30 p.m.

"As an alternative, customers are advised to use A, C or J train service at Broadway Junction," the MTA said on its website. "Customers can transfer between the L and the M trains at Myrtle Av for service to Manhattan. From Lorimer St, take the G."

"Allow additional travel time," the MTA said.

The fire broke out in an MTA vault located "five grades below street level" on the southbound L train tracks inside the Canarsie Tube just before 9:30 a.m., according to a spokesman for the Fire Department of the City of New York (FDNY). All trains were immediately halted between the Bedford stop in Brooklyn and the 8th Avenue stop in Manhattan.

Firefighters brought the blaze under control around an hour later, at 10:30 a.m.

Thursday's shutdown — a foreshadowing, perhaps, of the dreaded Canarsie Tube construction project scheduled for 2019 — forced thousands of L train commuters to find another way into the city. In both boroughs, subway riders complained of being stranded in clogged subway stations.

By late afternoon, MTA crews were still at the scene of the fire, with no estimation as to when the Canarsie Tube would be ready for re-opening.

It was a rough 24 hours on the L train: On Wednesday around 5 p.m., during the evening commute, a 46-year-old man was killed when he jumped in front of the train at Halsey Street near Bushwick, according to police. The man jumped onto the tracks and laid down directly in front of a Brooklyn-bound train, police said. He was pronounced dead on the scene at 5:27 p.m.

Photo by @MattyHumps/Twitter