The historic Lapstone Zig Zag Walk is a scenic bushwalking trail in Glenbrook that follows the path of an old railway built in the second half of the 19th century.
The track leads to the Top Points Lookout and the Knapsack Bridge, an impressive sandstone arch viaduct that once carried the Zig Zag Railway line across Knapsack Gully.
| Lapstone Zig Zag Walk (to Knapsack Gully) | |
|---|---|
| Distance: | 3 km (return) |
| Duration: | 1.5 hours |
| Grade: | Moderate (steep sections) |
| Wheel-friendly: | Yes (until the Top Points Lookout) |
| Dog-friendly: | Yes (on a lead) |
Getting There
The walking track starts from the small car park at the very end of Knapsack Street in Glenbrook (see map).
To get there, turn into Knapsack Street from the Great Western Highway and look out for the large blue RAAF signpost.
An alternative way to reach the Knapsack Viaduct is via the car park at the start of Mitchells Pass, further north in Glenbrook (see map).
The walk from there to the viaduct follows the former Great Western Highway and is an easy, flat trail.
The map below shows the Lapstone Zig Zag Walk from the Knapsack Street car park to the Top Points Lookout, from where you can walk down the stairs to the bridge.
Track Notes
The Lapstone Zig Zag was a railway section between Emu Plains and Blaxland stations on the Main Western Railway, with the Knapsack Viaduct built as part of this route.
The walking track to the viaduct is moderately challenging, mainly due to a few steep climbs. Other than that, it’s a fairly easy, family-friendly walk, suitable for all ages and fitness levels.
1. Quarry Lookout
Once you’ve parked your car, head into the bush at the large signpost to begin the hike to the Knapsack Viaduct along the old Lapstone Zig Zag railway line.
The first part of the walk follows an accessible, shared asphalt path, approximately 900 metres long, leading to the Top Points Lookout.
But before you get there, there are a couple of other highlights worth pointing out, such as the Quarry Lookout. The side trail to this lookout is clearly signposted (see picture above).
The Quarry Lookout isn’t particularly spectacular, but if you’re not in a rush, it’s worth a quick detour.
2. Lucasville Station
Towards the end of the sealed walking path is Lucasville Station, but it’s easy to miss if you’re not looking for it.
The old Lucasville railway station opened in 1877 to serve Australian politician John Lucas, who owned a house nearby.
That house, also called Lucasville, is now gone, but traces of its access paths and gardens are still visible. You might spot these remnants by walking up the concrete stairs at the station and heading into the bush.
After years of neglect, there’s not much left of Lucasville Station, but that’s part of what makes it so intriguing.
3. Top Points Lookout
At the end of the sealed section of the Lapstone Zig Zag Walk, you’ll find the newly built Top Points Lookout.
This large, elevated platform offers panoramic views over the Cumberland Plain, Knapsack Gully, and the Knapsack Bridge.
While the views are partly obscured by trees, it’s still a scenic and worthwhile lookout to visit.
4. Knapsack Stairs
Once you’ve finished admiring the views, it’s time to descend via the Knapsack Stairs to the Knapsack Bridge.
It’s a fairly steep descent with over 100 wooden steps—easy enough on the way down, but more of a challenge on the way back up.
By going down the stairs, you’re essentially moving from one section of the old zigzag railway line to another, lower on the escarpment.
When you reach the top of the bridge, it’s hard to believe this remarkable piece of engineering was built nearly two centuries ago.
5. Knapsack Bridge
The first railway into the Blue Mountains was the Lapstone Zig Zag, designed by John Whitton and built by William Watkins. To gain height and conquer the steep escarpment between Emu Plains and Blaxland, a zigzag railway design was deemed necessary.
This unique line was constructed between 1863 and 1865 and officially opened in 1867. As part of the project, the Knapsack Bridge, a sandstone arch viaduct, was built to carry the railway across Knapsack Gully.
The Lapstone Zig Zag was the first zigzag-designed railway in the world to be built as part of a larger main-line railway.
While it was considered a success, the Lapstone Zig Zag was closed in 1892 following the construction of a deviation of the Main Western Railway via Glenbrook. That first deviation was later replaced by a second Glenbrook deviation, which remains in use today.
After the Zig Zag railway closed, the Knapsack Viaduct continued to serve as part of the first Glenbrook deviation. However, it was bypassed with the second deviation and fell into disuse.
In 1926, the Knapsack Bridge was given a second lease on life when it became part of the former Great Western Highway. This continued until 1993, when the construction of the M4 Western Motorway bypassed the old highway.
Since 1995, the Knapsack Viaduct has been open to the public as part of the Lapstone Zig Zag walking track. Both the Lapstone Zig Zag and the Knapsack Viaduct are heritage-listed.
6. Knapsack Gully
For the best views of the bridge, it’s well worth doing the walking trail that leads down into the gully. That’s where you’ll get to see the bridge from below.
From the side of the bridge, at the bottom of the Knapsack Stairs, follow the walking path underneath one of the smaller arches.
As you make your way down into the valley toward the Knapsack Gully crossing, the views of the bridge keep getting better.
It’s a fairly steep descent into the gully, but it’s a short section, and the path is relatively easy to follow.
| Knapsack Viaduct stats | |
|---|---|
| Opened: | 1867 |
| Arches: | 7 |
| Height: | 40 metres above the gully |
| Length: | 120 metres |
| Original width: | 9 metres |
