Two viaducts south of Montrose were designed by Sir
Thomas Bouch, the architect of the original Tay Bridge but, due to delays in building the Tay Bridge and the line by
Dundee, they were not built until 1879. The more northerly bridge, the
South Esk Viaduct, was of iron
lattice girder construction. Following the
Tay Bridge disaster of 1879, the viaduct was inspected and, although the plans showed a straight structure, it was found to have a distinct curve. As well, many of the
piers were not perpendicular. Before the line could be opened to traffic in 1881, the bridge had to be dismantled and rebuilt by Sir
William Arrol, to a design by
W. R. Galbraith. The replacement was also of wrought iron lattice girder construction, based on designs dating back to the 1830s. The more southerly brick viaduct, the Ferryden Viaduct, was retained. ==Kinnaber Junction and the "Race to the North"==