Consisting of 48 arches that span 70-feet each, the Rockville Bridge was completed in 1902 and is still thought to be the longest stone masonry arch railroad bridge on the planet. At 3,820 feet, it spans the Susquehanna River about five miles north of Harrisburg, Pennsylvania and is still used by the Norfolk Southern Railway and Amtrak. It was constructed by the Pennsylvania Railroad after both the frequency and weight of its trains increased along its Philadelphia to Pittsburgh mainline at the turn of the 20th century. The bridge was added to the National Register of Historic Places in 1975.
railroad bridge at this location was of a wooden Howe truss design that was
completed in 1849 that, surprisingly, remained in service until a double-track
iron replacement was built in 1877. However,
as the number of trains crossing this bridge increased as did the weight of their
loads, the Pennsylvania Railroad’s Chief Engineer, William Henry Brown, decided
to replace it with a more permanent stone and concrete structure. He, and Assistant Engineer H. S. Righter then
designed the current 48-arch structure.
Their new bridge would be 52-feet wide in order to accommodate four tracks
and the arches would be divided into six groups based upon the size of their abutment
piers. Most of the abutment piers are
eight-feet wide, with every 8th abutment being 19 -feet wide to
strengthen the overall structure and increase stability.
Pennsylvania Railroad then contracted with two Philadelphia construction
companies, Drake and Stratton to build from the eastern side of the river and
H. S. Kerbaugh, Inc. to work from the western side. Construction began in 1900 and was overseen
by Assistant Engineer George Nauman. The
companies employed over 800 workers, many of them Italian immigrants, to include
300 skilled stone masons, to complete the bridge over the course of two
years. These workers used over 270,000
tons of sandstone mined from quarries located around Curwensville in Clearfield
County, Pennsylvania. They also filled
the abutments and spandrel walls with over 600,000 barrels of concrete to
increase the pace of construction and lower costs.
Bridge was completed in 1902, at a total cost of approximately $1 million, and
has remained in service, with few renovations or alterations, ever since. During the World Wars armed guards patrolled
the bridge as it was thought to be an enemy target. It gained recognition when it was featured in
the Pennsylvania Railroad’s popular wall calendar in both 1925 and 1926 it has
survived numerous floods to include those of 1936, 1972, and 2010.
One of its
lines was removed in the 1980s and another was eliminated after an intermodal
shipping container was blown off a train and into the river in 2010. In 1997, a spandrel wall at pier 19 failed
after it was weakened by the numerous freeze-thaw cycles it had endured and a
heavy coal train rolled overhead. Tons
of stone, coal, rails, ties and four hopper cars plunged into the river. It was then repaired with reinforced concrete
and finished with a surface that resembles the stone around it. Today, the Rockville Bridge still carries
hundreds of trains per year across the Susquehanna River and should do so into
the foreseeable future.