Knapsack Bridge was designed by John Whitton, Engineer-in-Chief for the railways. The seven sandstone arches across Jamison Creek are five and a half metres wide and thirty-eight metres high. Up until 1913 when the Glenbrook deviation was built, the Knapsack Bridge formed part of the Lapstone Zig-Zag. It was reopened to road traffic as part of the Great Western Highway in 1926 and finally closed in the 1990s.
