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"At Rockville, just above the capital city, they have thrown across the Susquehanna a four-track bridge of monolithic stone seven-eighths of a mile long and stepped in graceful arches as enduring as the mountains that look down on the beautiful river. . . . it has been built to last forever."
- Writer and novelist Frank H. Spearman, The Strategy of Great Railroads, 1904.

Old Rockville Bridge, circa 1892
Credit: Courtesy of the Railroad Museum of Pennsylvania, Operated by the Pennsylvania Historical and Museum Commission

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. 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.

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. The piers and spandrels (the area between the arches) are filled with concrete, making it technically a composite structure. In all, the bridge required not only 220,000 tons of stone but an estimated 600,000 barrels of cement. Measuring 3,820 feet long, it carries four tracks at an elevation fifty-two feet above the river's low-water mark. The price tag was $975,150. The bridge opened on March 30, 1902. 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.

Because the bridge was considered to be a military target, armed guards protected it during World Wars I and II. It got a boost of publicity in 1925 and 1926, and again in 1950, when PRR featured it on its widely known wall calendar series. The bridge withstood the flood of March 1936 and an even heavier assault from Tropical Storm Agnes in June 1972. By contrast, the 28-arch stone Shocks Mill Bridge, built thirty miles downstream by one of the two contractors who built Rockville, washed out in the Agnes flood.

In 1968, ownership of Rockville Bridge changed to Penn Central when PRR merged with the former New York Central Railroad. Penn Central went into bankruptcy in 1970, and became part of the government-backed rescue plan called Conrail in 1976. Conrail brought the railroad into the black, returning it to private investors in 1987.

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). 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. The repair and cleanup cost about $1 million, approximately the original price of the entire bridge. 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.

To the very end of the Pennsylvania Railroad's corporate existence, Rockville Bridge remained the largest of the company's 10,107 bridges. Though PRR built other large stone-arch bridges after Rockville, within a few years the construction industry had perfected the technology of reinforced concrete. Still later, pre-cast concrete sections and welded steel girders came into favor. As a result, the art and craft of the stone mason's skill fell into disuse, but remains spectacularly showcased at Rockville.

CREDITS:
Dan Cupper, Rockville Bridge: Rails Across the Susquehanna (Halifax, PA: Withers Publishing, 2002).
Ed. Morgan, The Quarries of Curwenville: the People, the Legacy (NP, ND).
Henry O. Tyrell, History of Bridge Engineering (Chicago: 1911).
William Shank, Historic Bridges of Pennsylvania (York, PA: American Canal and Transportation Center, 1974).
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