 |
| Knapsack Viaduct c.1880 |
For the early train travellers, rattling across the
Emu Plains in the late 1860s and 1870s, the seven classical, white sandstone
arches of the Knapsack Viaduct
must have presented an inspiring sight with which to begin their
ascent of the Blue Mountains. The construction of the viaduct, the like of
which no native-born colonial had ever seen, reaffirmed their nineteenth
century faith in Man's mastery of Nature, a faith which, in the colony's short
history, had often seemed threatened by this range of mountains.
In order to avoid costly
tunnels, the Engineer-in-Chief of the NSW Railways, John Whitton, proposed the
construction of zigzags on both the eastern and western flanks of the Blue
Mountains, known as the Lithgow or Great Zig Zag and the Lapstone or Little Zig
Zag respectively. In Whitton's words, the bridge 'consisted of five spans of
fifty feet and two of twenty feet each, built in masonry . . . for a single
line of railway on an incline of 1 in 30'.
The contract for construction was let to W. Watkins in
March 1863, and the work was completed in 1865. The bridge was constructed of
sandstone quarried in the neighbourhood, and carried a single rail line. The
construction work brought hundreds of people to Lapstone, and later, employees
of the railways to service it. The construction workers camped near their work
sites, often with their families. The
seven arched viaduct at Lapstone was hailed as a landmark of Australian
engineering and the finest piece of masonry in New South Wales when it opened
in 1867.
When the line was opened to
traffic from Penrith to Bowenfels in October 1869, ease of travel by the new
railway almost immediately began to broaden the public perceptions of the value
and worth of the Blue Mountains. When the western line was extended to Bathurst
in 1876, a new period of settlement and tourism was already underway. The track
included a now abandoned station called Lucasville which was built for the
Minister for Mines, John Lucas who had a holiday home nearby.
 |
| Lapstone Zig Zag plan showing both viaducts and roads |
The Railway Guide of New South
Wales, 1879 described the journey toward the viaduct from Penrith, and then the
structure itself, rather more romantically, 'the Railway may be seen winding
upwards - past huge rocks and steep declivities, alternating with dense woods;
the noble viaduct across Knapsack Gully being hence already distinguishable . .
. You have by this time arrived at the Knapsack Gully Viaduct - boldly erected
across a steep and stony gorge by the genius of the Engineer in Chief, John
Whitton. This admirable and imposing structure (which Imperial Rome . . . might
have been proud to claim) consists of seven successive arches'. Nell Aston in
1988 imagined the view from the train as it crossed the Knapsack Viaduct before
ascending the Zig Zag writing, 'it must have seemed like flying'.
Nevertheless, in the years that followed, the railway
landscape on the eastern escarpment underwent significant modification and the
place of the viaduct in the scheme of things was destined to change. By the
turn of the nineteenth century the increase in the volume of freight on the
western line and the restrictions on the length of trains imposed by the Zigzag
meant it had become uneconomical and Whitton’s masterpiece was gradually
replaced by tunnels and deviations and the Lapstone viaduct was abandoned. The
Zig-Zag itself was replaced in the early 1890s by a tunnel through the ridge
over which it had allowed access. While this first deviation did not affect the
role of the viaduct, such was not the case twenty years later when a second
deviation, of considerably greater magnitude, was constructed through Glenbrook
Gorge.
 |
| Fire's On, Arthur Streeton, 1891 |
In 1891 the artist Arthur Streeton visited the
Lapstone Hill tunnel site and painted his famous picture ‘Fires On’. The
painting captures a critical moment during the construction of the railway
line: the death of a railway worker in an explosion. 'Fire's on' was the
warning call before the blast, as the gang dynamited the tunnel through the
hillside.
Opened in 1913, the new route represented a dramatic
change and included a new viaduct over Knapsack Gully, lower down than the
original it replaced. Only seventy-five feet above the creek bed, this second
viaduct was on a curve and built of brick. With its phasing out as a part of
the rail route over the Blue Mountains the old nineteenth century Knapsack
Viaduct was, however, soon to find a new role as part of a very twentieth
century system of transportation.
The advent of the motor car focused attention upon the
condition of many of the State's roads including the Main Western Road up Mitchell's
Pass. A more suitable route was sought and, in October 1926, the viaduct was
taken over by the Department of Main Roads and incorporated into the route of
the Great Western Highway, and in response to increasing traffic the road deck was
widened to 30 feet (9.1m) in 1939. With the opening of the M4 motorway
extension in 1993 the viaduct was closed to traffic completely and developed of
a tourism and heritage precinct commenced.
In 1995 the bridge was reopened for pedestrian access, along with the John
Whitton Memorial Reserve, by Member for Macquarie, Maggie Deahm.
 |
| Lapstone Zig Zag Walking Track |
For those willing to pause from their travels for a
time, a walking track winds down from the old Lucasville Station, through the
arches of the viaduct to the floor of the gully, across Knapsack Creek and up
the opposite slope to Elizabeth Lookout. From this track visitors can observe
closely the graceful, arched contours of the viaduct and discern the solid
nature of its construction which so impressed our colonial forebears. Despite
being overshadowed later by its grander cousins on the western flank of the
mountains, the Knapsack Viaduct was one of the early achievements that helped
to encourage the fledgling Australian self-confidence.
Dimensions
Length of each of the 5 main spans: 15.2m
Smaller spans at each end: 6.1m
Maximum pier height from deck to rock: 40m
Links:
References:
Knapsack Viaduct, Lapstone. In: Historic Blue Mountains, John Low (1987).
Rails, Roads and Ridges, History
of Lapstone Hill- Glenbrook. Nell Aston, for the Glenbrook Public School
Centenary Committee (1988)
Links: http://www.slideshare.net/srnsw/ble-mountains-railway-the-train-that-thought-it-could
Local Studies Librarian, 2016
