![]() ![]() While the terminal deserves more in depth coverage, the Rockville Bridge and supporting approaches particularly on the West Bank in Marysville, represent the forward thinking of PRR engineers in designing and managing traffic flow of passenger, thru freight and terminating/ originating freight without interference and delay. This area of the PRR was the Eastern Hub of lines coming from New York, Philadelphia, Baltimore, Buffalo, and Hagerstown, creating a westward funnel, concentrating mainline traffic to Pittsburgh and points west. Built by the Pennsylvania Railroad, the 3820' long span is made of 48 seventy foot spans over the Susquehanna River, connecting the PRR Harrisburg Terminal and Buffalo Line with the Mainline West, and connection to the sprawling Enola Yard complex through a complex junction in Marysville PA. As a result, the art and craft of the stone mason's skill fell into disuse, but remains spectacularly showcased at Rockville.Opened in 1902 under the direction of Chief Engineer William H Brown, the Rockville Bridge is the longest masonry arch railroad viaduct in the world. Still later, pre-cast concrete sections and welded steel girders came into favor. Though PRR built other large stone-arch bridges after Rockville, within a few years the construction industry had perfected the technology of reinforced concrete. To the very end of the Pennsylvania Railroad's corporate existence, Rockville Bridge remained the largest of the company's 10,107 bridges. Since then, crews have strengthened the structure with steel tie-rods and braces, a process that continued under the ownership of Norfolk Southern Corporation, which added this portion of Conrail to its system on June 1, 1999. The repair and cleanup cost about $1 million, approximately the original price of the entire bridge. When a heavy coal train passed over the weakened spot, the south spandrel wall failed, sending tons of stone, rails, ties, and four 100-ton loaded hopper cars into the Susquehanna. On August 19, 1997, the accumulated effect of repeated freeze-thaw cycles forced some of the bridge's stones out of alignment at Pier 19 (the nineteenth pier from the east shore). Less than three months later, the railroad inaugurated the most famous regularly scheduled passenger train to use the structure: the overnight New York-Chicago Pennsylvania Special, which later became the Broadway Limited. Measuring 3,820 feet long, it carries four tracks at an elevation fifty-two feet above the river's low-water mark. In all, the bridge required not only 220,000 tons of stone but an estimated 600,000 barrels of cement. The piers and spandrels (the area between the arches) are filled with concrete, making it technically a composite structure. Today, many people call Rockville Bridge "the longest stone-arch bridge in the world," but that's only partly true–only the visible outer layer of its form is stone. Each of the forty-eight arches measured seventy feet long, and the four arches at each end gently curved to accommodate the swing of the tracks as they turned to parallel the river. The Rockville Bridge required the expertise of as many as 300 stonemasons, Italian immigrants or Italians who relocated from Curwensville in Clearfield County, site of some of Pennsylvania's largest quarries and source of much of the sandstone used in the bridge. Under Brown's hand, contractors installed mainline stone-arch bridges at the rate of two or three a year, in sizes and varieties that ranged from a single arch to the majestic forty-eight-arch Rockville Bridge near Harrisburg. Beginning in 1888, he decreed that replacement bridges on PRR's busiest routes, including its Philadelphia-Pittsburgh main line, would reflect a revival of stone-arch technology. ![]() As a result, Brown soon began pushing the idea that only costly stone-arch bridges -like those used in the earliest days of railroading - were durable enough to withstand both the passage of time and the growing number of mainline freight and passenger trains. Though iron was stronger than wood, spectacular and often tragic failures on some railroads showed what could happen when iron spans were overloaded and under-maintained. And with the growth of business, PRR's main line no longer carried a mere seven trains a day but as many as 100. Some even went up in smoke from sparks spewed from the stacks of passing steam locomotives. Wooden bridges that were perfectly adequate in the 1840s quickly began to wear out. As the United States matured into an industrialized nation after the Civil War, the trains that moved the nation forward grew longer, heavier, faster, and more frequent. And this amazing stone bridge, composed of 220,000 tons of stone that took 800 workers two years to build, also stands as a monument to overcoming frustration. Rockville Bridge, an icon of railroad engineering, is the crowning achievement of William Henry Brown, chief engineer of the Pennsylvania Railroad. ![]()
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