The Allegheny Portage Railroad was the first railroad constructed through the Allegheny Mountains in central Pennsylvania, United States; it operated from 1834 to 1854 as the first transportation infrastructure through the gaps of the Allegheny that connected the midwest to the eastern seaboard across the barrier range of the Allegheny Front. Approximately 36 miles (58 km) long overall, both ends connected to the Pennsylvania Canal, and the system was primarily used as a portage railway, hauling river boats and barges over the divide between the Ohio and the Susquehanna Rivers. Today, the remains of the railroad are preserved within the Allegheny Portage Railroad National Historic Site operated by the National Park Service.
The Smithfield Street Bridge is a lenticular truss bridge crossing the Monongahela River in Pittsburgh, Pennsylvania, USA.
The West End Bridge is a steel tied-arch bridge over the Ohio River in Pittsburgh, Pennsylvania, approximately 1 mile (1.6 km) below the confluence of the Allegheny and Monongahela Rivers. It connects the West End to the Chateau neighborhood on the North Side of Pittsburgh.
New Market, as it was originally known, and later also known as Head HouseMarket and Second Street Market, is a historic street market on South 2nd Street between Pine and Lombard Streets in the Society Hill neighborhood of Philadelphia, Pennsylvania. With a history dating to 1745, it is one of the oldest surviving market buildings of its type in the nation. This portion, which survives from a longer structure originally extending all the way to South Street, was designated a National Historic Landmark in 1966, and is the centerpiece of the Head House Square historic district.
The Insurance Company of North America Building is a historic commercial building in downtown Philadelphia, Pennsylvania, United States. Built in 1925, it was for many years the home of the Insurance Company of North America (INA), the nation's first and oldest joint-stock insurance company. It was designated a National Historic Landmark in 1978. The building, occupied by INA until 1991, has been developed into condominiums.
The Edwin Forrest House is a historic house and arts building at 1346 North Broad Street in Philadelphia, Pennsylvania. Built in 1853–54, it was from 1880 until 1960 home to the Philadelphia School of Design for Women, at one time one of the nation's largest art schools for women. The house was designated a National Historic Landmark in 1993 for this association.
The Middlefield–Becket Stone Arch Railroad Bridge District is a historic district extending through parts of the towns of Chester, Middlefield, and Becket, Massachusetts. The district encompasses a 3.7-mile (6.0 km) stretch of railroad right of way in which there are ten bridge crossings, including nine over the west branch of the Westfield River. The bridges were built in four time periods: 1840, 1866, 1912, and 1928. Nine of the ten bridges are stone or concrete masonry work, and one is a truss girder bridge. All are, with only minor exceptions, in excellent and original condition. The bridges were built to carry the Western Railroad through on its run from the Connecticut River to the Hudson River. This section of railroad was the most expensive the company had to build, costing over $1 million in 1840.
Choate Bridge (1764) is a historic stone arch bridge carrying Route 1A/Route 133 over the Ipswich River in Ipswich, Massachusetts. It is one of the oldest surviving bridges in North America, and is probably the oldest in Massachusetts. It was listed on the National Register of Historic Places in 1972 and also has been designated as a National Historic Civil Engineering Landmark.
A skew arch is a method of construction that enables an arch bridge to span an obstacle at some angle other than a right angle. This results in the faces of the arch not being perpendicular to its abutments and its plan view being a parallelogram, rather than the rectangle that is the plan view of a regular, or "square" arch.
The Wilmington Rail Viaduct is a series of fills and bridges, about 4 miles (6.4 km) long, that carries the Northeast Corridor through the city of Wilmington, Delaware, above street level. Constructed between 1902 and 1908, the structure consists principally of fills supported by heavy stone retaining walls, punctuated with plate girder bridges over streets, and augmented by a few sections of brick arch viaduct. Its construction is typical of the Pennsylvania Railroad's architectural practices at the time, and the viaduct has been documented by the Historic American Engineering Record and listed on the National Register of Historic Places. Built by the Pennsylvania Railroad (PRR) as part of a series of grade crossing eliminations along the Northeast Corridor, the elevation of the rail line necessitated several other changes to rail infrastructure in Wilmington, including the construction of the Wilmington Shops at the east end of the viaduct, and the construction of the Wilmington Station and adjacent Pennsylvania Railroad Office Building along the elevated right-of-way.
Hereford Road Skew Bridge is a disused railway bridge in Ledbury, Herefordshire. Built in 1881 to carry the Ledbury and Gloucester Railway across the Hereford Road at an angle of approximately 45°, it was built as a ribbed skew arch with stone spandrels and wing walls, and ribs of blue brick. The railway line was closed in 1959 and the bridge is now used as part of the Ledbury Town Trail footpath.
The Philadelphia and Reading Railroad, Schuylkill River Viaduct, also called the Reading Railroad Bridge and the Falls Rail Bridge, is a stone arch bridge that carries rail traffic over the Schuylkill River at Falls of Schuylkill in Philadelphia, Pennsylvania. Located in Fairmount Park, the bridge also spans Martin Luther King, Jr., Drive, and Kelly Drive. The name Philadelphia & Reading Railroad (P&R) was later shortened to Reading Company.
The Pithole Stone Arch Bridge is a 37-foot (11 m) masonry, deck arch bridge that spans Pithole Creek between Cornplanter and President Townships, Venango County in the U.S. state of Pennsylvania. The bridge was listed on the National Register of Historic Places in 1988 and was documented by the Historic American Engineering Record (HAER) in 1997.
The Skew Arch Bridge in Reading, Pennsylvania, also known as the Askew Bridge and nicknamed the Soap and Whiskey Bridge, is a historical skew arch bridge completed in 1857 carrying two tracks of the Philadelphia and Reading Railroad (P&R) at an angle over Sixth Street in Reading, Berks County, Pennsylvania. The bridge was acquired by Conrail after the P&R's demise in 1976, and was transferred to Norfolk Southern Railway in 1999.
The Perkiomen Bridge, originally built 1798-99 and widened in 1928, is one of the oldest stone arch bridges in the United States still in use. It crosses Perkiomen Creek near Collegeville, Pennsylvania. The bridge's six semi-circular arches cover a total of over 300 feet (91 m). The longest arch spans 76 feet (23 m). Its decorative piers and belts courses are unusual for a bridge this old. A lottery financed $20,000 of the original construction. The bridge carried the main road from Philadelphia to Reading, known at various times as the Manatawny Pike, Germantown Pike, the Philadelphia-Reading Pike, and US 422. Since the construction of the US 422 bypass, the road has been known as Ridge Pike or Old US 422.
Bridge in Snake Spring Township, also known as the Narrows Bridge, is a historic concrete arch bridge located at The Narrows in Snake Spring Township in Bedford County, Pennsylvania. It was built in 1934, and is a 580-foot-long (180 m), open spandrel concrete arch bridge with five arches. The roadway is skewed and carries US 30, the Lincoln Highway, over the Raystown Branch Juniata River.
Pennsylvania Railroad Old Bridge over Standing Stone Creek, also known as Conrail Old Bridge over Standing Stone Creek, is a historic multi-span stone arch bridge spanning Standing Stone Creek and located at Huntingdon, Huntingdon County, Pennsylvania. It was built by the Pennsylvania Railroad between 1848 and 1850. It was in use until 1892, when the main line was relocated onto the former Pennsylvania Canal bed. A second stone arch bridge was constructed nearby for the new alignment.
Chester Waterside Station of the Philadelphia Electric Company is a historic former coal-fired power station, located on the Delaware River in Chester, Delaware County, southeastern Pennsylvania.
The Clarence B. Moore House is a historic home located at 1321 Locust Street at the corner of S. Juniper Street between S. 13th and S. Broad Streets in the Washington Square West neighborhood of Philadelphia, Pennsylvania. The Moore house was built in 1890 and was designed by architect Wilson Eyre as the home of the merchant, archaeologist, and writer Clarence Bloomfield Moore (1852-1936). It sits next to the Dr. Joseph Leidy House, which Eyre designed in 1893.
The West Sixth Street Bridge is a historic stone arch bridge in downtown Austin, Texas. Built in 1887, the bridge is one of the state's oldest masonry arch bridges. It is located at the site of the first bridge in Austin, carrying Sixth Street across Shoal Creek to link the western and central parts of the old city. The bridge was added to the National Register of Historic Places in 2014.
US 13 (Thirty-third Street) over Master St., Philadelphia, Pennsylvania 
The single span stone arch, looking west
Looking east
Looking west
Interior stone and brickwork
Detail at west end
