By CBS3 Staff

PHILADELPHIA (CBS) — A heads up if you plan to take the SEPTA trolley to Center City in the next two weeks. SEPTA is doing its Trolley Tunnel Blitz from 10 p.m. Friday until July 25.

This is so crews can replace worn tracks and overhead wires, work on signals and rebuild the 22nd Street platform.

Service will begin and end at 40th and Market Streets.

SEPTA says you should use the Market-Frankford line from there if you need to get into Center City.