To avoid swampy areas and serve more populated ones, the PW&B built the Darby Improvement, which diverged from its existing main line just south of the Grays Ferry Bridge, passed through Darby, and rejoined it at Eddystone, just upriver from Chester. The new inland track opened on November 18, 1872. The PW&B dispensed with the 9.9-mile old alignment less than a year later, leasing it on July 1, 1873, to the Philadelphia and Reading Railway for 999 years with the stipulation that it would be used solely for freight. (The Reading dubbed the line, along with some connecting track, its Philadelphia and Chester Branch; southbound trains reached it via the Junction Railroad (jointly controlled by PW&B, Reading, and PRR) and continued on to the connecting Chester and Delaware River Railroad.)