By Don Ford

SAN FRANCISCO (KPIX 5) — Starting next Monday night at 9:30 p.m., the SFMTA will shut down the Muni tunnel between the Embarcadero and West Portal stations so crews can repair aging systems.

This is the same tunnel where 1,000 feet of overhead power line came loose last April, snagging a train disabling Muni Metro service underground for nearly the entire length of Market Street. It took all day to make emergency repairs while folks crammed into surface shuttle buses.

READ MORE: Elderly Asian Woman Stabbing Attack Triggers Blame Game Between San Francisco DA, Police Officers Assn

“So that was involving our overhead lines and that is one of the four major functions that we will be addressing,” said SFMTA Deputy Spokesperson Erica Kato.

Another serious tunnel problem is the automated train control system. Computers are supposed to handle the trains when they enter the tunnel.

“We do have some disruptions. When a train doesn’t connect to the system, it runs in manual at a slower speed,” explained Kato.

READ MORE: 1 Taken To Hospital, 2 Vehicles Damaged In Vegetation Fire Along Highway 101 In San Jose

Slower speeds mean congestion and slower service. That also effects surface operations when trains are running late.

Although officials are calling the maintenance routine, it is far from it. The scheduled nightly closure is expected to last two weeks. It will be one of the longest lasting tunnel maintenance and repair efforts in years.

“Crews generally only have two hours — if not less — at night, so this would really allow them to get in there and do the work,” said Kato.

MORE NEWS: Snakes by the Planes: Endangered San Francisco Species Found Thriving in Wetlands at SFO

Crews are also scheduled to work on track and train signal repairs during the closures that will last until regular morning service starts each day.