This magnificent railway viaduct, built between 1846 and 1850 in a combination of red and blue bricks, is far less well known than the famous Ribblehead Viaduct, located about 25 miles to the north, but in many ways, it is more impressive not least because it is longer. Taking the Blackburn to Clitheroe railway line across the valley of the River Calder, close to the border of Lancashire and Yorkshire, it is in a magnificent setting under the shadow of the famous, Pendle Hill, widely associated with the Pendle Witch Trials. It is located just on the southern edge of the Forest of Bowland Area of Outstanding Natural Beauty.

The viaduct consists of 48 elegant arches, two of which have a distinctive decorative brick infill. They look rather ecclesiastical from a distance and may have been introduced to reflect the importance of the 14th-century gatehouse of the nearby Whalley Abbey which the road serves. The gatehouse and abbey ruins are worth a visit in their own right.

At over 600 yards long, and 70 feet above the valley, the viaduct, known locally as the Whalley Arches,  required over six million bricks and over 12,000 cubic yards of stone to complete. During construction two of the arches collapsed, leading to three fatalities. The engineer was Terence Woulfe Flanagan who later constructed the railways between Antwerp and Rotterdam and between Lisbon and Santarem.

The line connects with lines in West and North Yorkshire.  It was closed to most passengers in 1962. It was kept open just for freight, and occasional passenger train diversions (due to track maintenance elsewhere)  until 1994.  In 1994 a public campaign secured the re-opening of the line to passengers between Blackburn and Clitheroe (and onward to Hellifield on Sundays). Currently, the line is known as the Ribble Valley Line and serves both commuters and tourists.

In addition to the regular diesel-powered services the line often runs special steam-hauled heritage services for which the crossing of this amazing viaduct is one of the unadvertised highlights. Plans are in place to assist local tourism by re-opening the line fully to passengers to allow scheduled passenger trains to join the famous Settle to Carlisle line.