The Junction Railroad was incorporated on May 3, 1860, to connect the Reading, Pennsylvania, and PW&B lines through West Philadelphia, which sits across the Schuylkill from downtown. The three lines each bought a one-third share in the Junction Railroad on August 1, 1861, and the company was organized on October 3. Construction began from Belmont to West Philadelphia in 1862, including trackage rights along the PRR between 35th Street (now Zoo interlocking) and Market Street; this opened on November 23, 1863. From West Philadelphia south to Grays Ferry, the Junction Railroad mostly paralleled the WC&P, and had to cross it somewhere, leading to a dispute between the two companies and a delay in opening the southern half. One track opened south of the WC&P crossing at Spruce Street in December 1864, giving a temporary routing via the WC&P through West Philadelphia. The final portion, from Market Street to Spruce Street, including the Market Street Tunnel, opened on July 1, 1866.