Welwyn Viaduct

The viaduct is around 1,560 feet (475 m) long and comprises forty arches of 30 ft (9 m) span, and is 100 ft (30 m) high from ground level to trackbed. It is built of brick fired from brick clay quarried on site during construction, and took two years to build, including the construction of embankments at both ends which required the movement of around one million tons of earth by human and horse power. It was designed by William Cubitt and styled after a Roman aqueduct.