Patterson Viaduct Bridge, 2006

Patapsco River at Ilchester, MD


Satellite View of Project Location View Larger Map
photo by Carroll Vogel

USE:  Pedestrian

SPAN:  164'


TOWERS:  39' tall, A 588 Weathering Steel

ANCHORS:  18' Wide Deadman Anchors

BACKSTAYS:  1" Galvanized Structural Strand

CABLESTAYS: 5/8" Galvanized Structural Strand

Patterson Viaduct Bridge, 2006

This Sahale Cable Stay Bridge is located on the Patapsco River at Ilchester, MD, between Baltimore and historic Ellicott City. As bridge building legacies go, this Sahale crew followed in some mighty large footsteps: Patterson Viaduct Footbridge is located in what is now Patapsco Valley State Park, on an abandoned railroad grade from the original Baltimore & Ohio Railroad (B&O).

Reported in many quarters as the first US railroad, construction of the first 13 miles of track began on July 4, 1828, from Baltimore west to Ellicott's Mills (now known as Ellicott City), opening on May 24, 1830. At Ilchester, the railroad crossed the Patapsco River and the early engineers, modeling their structures heavily on European influenced design, opted for stone as the building material of choice. Culverts, retaining walls, even the sleepers (or ties) of the early B&O were granite, and at Ilchester Engineer Caspar Wever and Builder John McCartney constructed a stone viaduct having two 55' primary arches and a 20' approach arch at either end. Named after prominent B&O stockholder William Patterson this robust structure was erected between May-December of 1829.

John McCartney's remarkable achievement earned him the contract (under Caspar Wever's direction) to later build the renowned Thomas Viaduct (also in Patapsco Valley State Park), a 612 foot curved masonry bridge that has been in continuous service since 1835, and still carries twin parallel tracks today.

McCartney's Patterson Viaduct stood at Ilchester until 1868, when three of the arches were wiped out by floods of historic proportions. By that time the B&O had abandoned stone construction as too expensive and the viaduct was replaced with a cable stayed truss bridge of Wendel Bollman design, sitting on stone abutments from the original viaduct. A self-educated engineer, Bollman patented his truss design on January 6, 1852, and went on to manufacture and construct roughly 100 such bridges (mostly for railroads) over a 20-year period. Bollman's truss incorporates cast iron compression members with wrought iron tension eye bar stays radiating downward and through the truss from an apex at the top of each tower. These manufactured bridges were an early industrial revolution success story in American railroading but wrought iron and cast iron were soon supplanted by other, stronger, lower maintenance bridges built of steel.

At the Patterson Crossing, Wendel Bollman's Truss stood for roughly 40 years before it too succumbed to flood, was replaced briefly by a temporary bridge, and then abandoned altogether in 1903 when the railroad was realigned through the new Ilchester Tunnel. Today, only a single representative example of Bollman's Railroad Truss remains, in nearby Savage, MD. For over 100 years there had been no bridge at Ilchester, only the stone masonry abutments and a single arch from the original viaduct standing in mute testimony to a past of grand dreams, and too-oft forgotten, achievement.

Ultimately, the indefatigable Charles Wagandt (a local entrepreneur and re-developer of historic Oella, MD) and the Friends of Patapsco Valley & Heritage Greenway prevailed in a 21st Century vision to see a bridge once again standing at Ilchester. The new Patterson Viaduct Trail Bridge and companion Grist Mill Trail Extension were dedicated on November 5, 2006, linking Ilchester to Patapsco Valley State Park and points beyond for pedestrians and cyclists alike. In recognition of the bridge builders in whose footsteps we followed Sahale selected a cable stay supported truss design for the bridge, to emulate the Bollman Truss from 1868. Additionally, the new bridge rests on John McCartney's original foundations from the Patterson Viaduct of 1829.

photo by Carroll Vogel

Bridge center through the trees.

photo by Steve Howell
Cable stay and truss hybrid construction.