Otford railway tunnel facts for kids
Quick facts for kids Overview |
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|---|---|
| Line | Illawarra railway, Otford, City of Wollongong, New South Wales, Australia |
| Coordinates | 34°12′48″S 151°00′01″E / 34.213221°S 151.000269°E 34°13′14″S 150°59′52″E / 34.220500°S 150.997667°E 34°13′19″S 150°59′50″E / 34.2220°S 150.9971°E 34°13′32″S 150°59′43″E / 34.225496°S 150.995338°E |
| Status | heritage |
| Start | Otford |
| End | Stanwell Park |
| Operation | |
| Closed | 1915 |
| Technical | |
| Length | 78 chains (5,100 ft; 1,600 m) |
| Gauge | 4 ft 8 1⁄2 in (1,435 mm) standard gauge |
| Highest elevation | 105 metres (344 ft) |
| Lowest elevation | 60 metres (197 ft) |
| Grade | 1:40 (2.5 %) |
The Otford railway tunnel is an old railway tunnel in New South Wales, Australia. It's located near Otford on the Illawarra railway line. This tunnel is considered a special heritage site. It was designed by the New South Wales Government Railways and built by W. Rowe, W. Smith, and Mr. McDonald. The tunnel was officially added to the New South Wales State Heritage Register in 1999.
Contents
History of the Otford Tunnel
The Otford Railway Tunnel was built in 1888. It was one of eight tunnels constructed on the Illawarra line between Waterfall and Clifton. This tunnel was a very important part of linking the northern and southern sections of the Illawarra railway line. It opened on October 3, 1888.
Building the Tunnel
The tunnel was made from brick arches. When it was first built, it was the longest and steepest tunnel on the railway system. It was about 5,985 feet or 1,824 metres long and had a steep slope, or gradient, of 1 in 40. This means for every 40 units of horizontal distance, the tunnel dropped 1 unit vertically.
Challenges with Steam Trains
The Otford tunnel, along with the Metropolitan tunnel, became famous for being very hot and smoky. This was especially true for the steam train crews climbing the steep section towards Waterfall. Sometimes, train drivers even got burned by the intense heat.
Because of these tough conditions, this single-line section became a "bottleneck." This means it slowed down train traffic a lot. Trains had to carry up to 50% less cargo to get through the steep area.
Solving the Smoke Problem
To help with the smoke, a large brick ventilation shaft was built in 1891. This shaft was 7 feet (2.1 m) wide and went down 200 feet (61 m) into the tunnel. Even with the shaft, smoke was still a big problem.
By 1904, plans were made for new tunnels, known as the "Helensburgh Deviation." This new route would bypass the old Otford tunnel. In the meantime, a powerful fan was installed in 1908 at the northern end of the tunnel to blow air through it.
Tunnel Closure and Later Uses
The new Helensburgh deviation was completed in 1915. The duplicated railway line could now completely bypass the Otford tunnel. Because of this, the Otford tunnel was closed on October 10, 1920.
After it closed, the tunnel was used for different things.
- It became a walking path, allowing people to walk between Otford and Stanwell Park.
- During World War II, in 1942-43, a part of the tunnel's roof was intentionally damaged as part of a special program.
- In 1959, a company called Eden Industries used the tunnel to grow mushrooms. They cleared away the damaged section and built a new concrete part to support the tunnel.
The tunnel was closed to the public in 2000 for safety reasons. Security gates were put at the southern entrance to stop people from entering.
What the Tunnel Looks Like
The Otford Railway Tunnel area includes the tunnel itself and its entrances. It also has the ventilation shaft. You can reach the southern entrance of the tunnel from Stanwell Park. The northern entrance is about 440 meters southwest of Otford Railway Station.
Inside the Tunnel
The tunnel is made of concrete and brick arches. It is about 1824 meters long and used to have a single railway track. Originally, there was a special drain made of sandstone slabs running through the tunnel. However, much of this sandstone has been removed over time. The old track and drain are now about 1.3 meters below the current surface. The brick ventilation shaft, built in 1891, is located about halfway along the tunnel.
Tunnel Condition
As of 2010, the tunnel was in fair condition. The southern entrance needed new steel gates to keep out animals and people. The condition of the old track bed and drain inside the tunnel varies in different places. The tunnel is mostly intact, except for the section that was damaged in 1942-43 and then repaired with concrete. Some of the original sandstone from the drain is also missing.
Why the Tunnel is Important
The Otford Railway Tunnel is very important to the history of New South Wales. It is listed on the State Heritage Register because of its historical and technical significance.
Historical Importance
- The tunnel was a huge engineering project built in 1888. It was crucial for connecting the Illawarra railway line to Sydney.
- It was part of a very steep section of the railway line that caused many problems for steam trains in the late 1800s.
- The tunnel was later bypassed by the Helensburgh deviation in 1919, showing how railway technology improved over time.
- It was also used during World War II as part of a special program.
Technical Importance
- The Otford tunnel was a major engineering achievement for its time. It was the longest and steepest single-line tunnel ever built in Australia when it opened.
- The special ventilation system built to deal with the smoke problems shows the challenges engineers faced. It also shows how they tried to solve them.
- Studying the tunnel can help us understand how tunnels were built in the late 1800s. It also shows early uses of concrete in construction.
Rarity and Representation
- The Otford tunnel is rare because it's an almost untouched tunnel from 1888. It was built specifically for steam trains on the difficult Illawarra line.
- It is a good example of the tunnels built by Rowe & Smith for the Illawarra line.
