SACRAMENTO (CBS13) — Lanes on the Tower Bridge will be closed starting on Monday as Caltrans performs mechanical and electrical upgrades.

Only one lane will be open in both directions from 7 a.m. to 7 p.m. from Monday through Thursday Sept. 27.

Additional full closures are being floated for early October, tentatively on Oct. 4, 8 and 9.

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Work on the bridge comes more than a month after the Rio Vista Bridge on Highway 12 was closed due to mechanical problems. The bridge was stuck in the upright position and had to be lowered manually. The bridge was closed occasionally to raise the bridge manually to allow boats to pass underneath.

The Tower Bridge work was originally supposed to start in May, then was delayed until July, and is finally set to happen next week.