By CBS3 Staff

PHILADELPHIA (CBS) — SEPTA has finished a 17-day blitz of repairs and maintenance that went on for 24 hours a day. SEPTA provided a video of the 2021 trolley tunnel blitz.

Every year, the tunnel is shut down during the slowest time of the year. That gives crews time to work on maintenance and other improvements.

Up to 300 workers were on site during each shift.

The tunnel reopened Monday morning.