In 1838, the B&O began service from Baltimore to Philadelphia using the new PW&B line. Connecting trackage in Baltimore ran from the B&O's Mount Clare terminal east along Pratt Street and East Falls Avenue to the PW&B's President Street Station. From there the PW&B ran east on Fleet Street and Boston Street before leaving onto its own right-of-way. In 1881, the B&O attempted to gain control of the PW&B, but lost the stock battle to the Pennsylvania Railroad, which informed the B&O that it would lose access to the PW&B line in 1884. This forces the B&O to build a new route to Philadelphia. It acquired the Delaware Western Railroad, which had a charter but no track, merged it into the Baltimore & Philadelphia in 1883, and began construction. The line was in full operation by 1886. Except at its two ends, the line was built within a few miles to the northwest of the PW&B. At the Baltimore end, the line ended in the Canton neighborhood, with a car ferry across the Patapsco River to Locust Point. At the Philadelphia end, the new line crossed the PW&B and its old alignment and crossed to the east side of the Schuylkill River on the new B&O Railroad Bridge, just south of the Grays Ferry Bridge. A branch split there towards the Delaware River, while the main line continued north along the Schuylkill, with a station downtown, and then passed through the Art Museum Tunnel to Park Junction with the Philadelphia and Reading Railway's main line; this tunnel, the last part of the line to be finished, opened on December 15, 1886. is the second bridge at this crossing, a steel truss double track design built between 1907 and 1910 near Perryville, Maryland. It replaced a single-track iron and steel bridge built in 1886 during the original construction of the line. The Reading, originally using the Junction Railroad west of the Schuylkill to access its Chester branch, obtained trackage rights over the Baltimore and Philadelphia, and the B&O obtained trackage rights over the Reading's lines from Philadelphia to Jersey City, New Jersey, across the Hudson River from New York City. The Baltimore and New York Railway and Staten Island Rapid Transit Railway provided their own freight terminal, at St. George on Staten Island. Though a surface alignment through downtown Baltimore was authorized by the Maryland legislature, the B&O instead obtained a charter for the Baltimore Belt Line to provide a completely grade-separated route. This new route entered the long Howard Street Tunnel at Camden Station, running north under downtown, and then turning east through two shorter tunnels to a junction with the Philadelphia Branch at Bay View Yard. The Baltimore Belt Line was completed in 1895, and its expenses drove the B&O to bankruptcy in 1896. The last passenger trains ran through the tunnel and over the Baltimore and Philadelphia in 1958; since then all traffic has been freight. The route is now operated byCSX as its Philadelphia Subdivision.
