Blue Mountains, Australia, Railway History

Lapstone Hill Railway Routes

First major obstacle on the Great Western Railway.



Lapstone Hill was the first major obstacle to be overcome in the construction of the railway over the Blue Mountains. As in the case of the road, various routes have been adopted over the years.

Related pages: History Plaza | Lithgow Zig Zag | Railway Services


Lapstone Zig Zag

Engineer John Whitton wanted to tunnel through the hill, but a tight budget prevented this, so a zig zag (or switch-back) was constructed. This device necessitates reversing the train up, or down, one of the three legs of the zig zag route. Gradients ranged from a steep 1 in 30 to 1 in 33.


Knapsack Viaduct

The route adopted involved an impressive sandstone viaduct over Knapsack Gully. The viaduct became the largest in New South Wales, being 388 feet long and 120 ft high with 5 spans of 55 ft and 2 of 20 ft.

Construction commenced in 1863. The line was opened to Weatherboard (now Wentworth Falls) on July 13, 1867.

A second, more spectacular zig zag was constructed on the western escarpment. Known as the Lithgow Zig Zag, it is now in use as a tourist railway.

Knapsack Viaduct, Lapstone, Blue Mountains. Originally built to carry a single railway track, the bridge was later fitted with a new concrete deck, enabling it to carry 2 lanes of road traffic. It formed part of the highway until being by-passed in the mid 1990's. Today it is used only by pedestrians and emergency vehicles.

The bridge is readily accessible to tourists; and is signposted from the motorway (Emu Plains exit).


Photo: David Martin


Zig Zag By-Passed

The single track zig zag suffered from being a bottleneck, and limiting the size of trains. In 1892, a deviation incorporating a tunnel through Lapstone Hill was opened. Steepest gradient was 1 in 31. Today the tunnel is used for growing mushrooms.


Glenbrook Gorge Route

The poorly ventilated tunnel caused severe passenger and crew discomfort, the gradient was still very steep, and further increases in traffic necessitated duplication of the line. In 1911, the present line through Glenbrook Gorge was opened. The grade was reduced to 1 in 60, a new brick viaduct constructed over Knapsack Gully, and Glenbrook Station re-located. This route remains in use to the present day.

Steam train climbs Glenbrook gorge, Blue Mountains. First train through Glenbrook Gorge, in 1911. Note the second locomotive assisting the climb. Locomotives are believed to be Beyer Peacock P-6 Class 4-6-0, later re-classified 32 class. Today, such a view would be obscured by trees, undergrowth and overhead power cables. Electrification was bad news for photographers!

Glenbrook Gorge is now part of the national park. Travellors to the Blue Mountains are advised to sit on the left side of the carriage, in the upstairs compartment, for the best views.


Electric & steam train services.....
Photo: Harry Phillips
Courtesy BMCL



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