Nepean River railway bridge, Menangle facts for kids
Quick facts for kids Nepean River railway bridge |
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Southbound view in June 2010
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| Coordinates | 34°07′05″S 150°44′37″E / 34.118033°S 150.743615°E |
| Carries | Main Southern railway line |
| Crosses |
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| Locale | Menangle, Southern Highlands, New South Wales, Australia |
| Official name | Menangle rail bridge over Nepean River |
| Other name(s) | Menangle Railway Bridge |
| Owner | Transport Asset Holding Entity |
| Maintained by | Australian Rail Track Corporation |
| Characteristics | |
| Design | Girder bridge |
| Material | Wrought iron |
| Pier construction |
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| Total length | 145.2 metres (476 ft) |
| Width | 7.8 metres (26 ft) |
| Longest span | 24.2 metres (79 ft) |
| Number of spans | 3 |
| History | |
| Designer | Sir John Fowler for John Whitton |
| Contracted lead designer | NSW Government Railways |
| Engineering design by | NSW Department of Public Works |
| Constructed by | Mssrs. Peto, Brassey and Betts |
| Fabrication by | Canada Works, Birkenhead, England |
| Construction begin | 1862 |
| Construction end | June 1863 |
| Opened | 1 July 1863 |
| Official name: Menangle rail bridge over Nepean River' | |
| Type: | State heritage (built) |
| Criteria: | a., c., d., e., f., g. |
| Designated: | 2 April 1999 |
| Reference #: | 1047 |
| Type: | Railway Bridge/ Viaduct |
| Category: | Transport - Rail |
| Builders: | Mssrs. Peto, Brassey and Betts |
The Nepean River railway bridge is a very old and important railway bridge in New South Wales, Australia. It carries the Main Southern railway line over the Nepean River near a town called Menangle. This bridge was built way back in 1863!
It was designed by John Whitton, who was a chief engineer for the New South Wales Government Railways. The company that built it was called Messers Peto, Brassey and Betts. This bridge is also known as the Menangle rail bridge over Nepean River or the Menangle Railway Bridge. It's so special that it's listed on the New South Wales State Heritage Register.
Contents
Building the Menangle Bridge
The Menangle Bridge was the very first large iron railway bridge ever built in New South Wales. It opened in 1863, which was a big deal for the railway system. Before this, the first large railway bridge was made of stone and opened in 1855 at Lewisham.
The parts for the Menangle Bridge were made in England. They were built at a place called The Canada Works in Birkenhead. These parts were then shipped all the way to Australia.
The bridge officially opened on 1 July 1863. This allowed the railway line to extend from Campbelltown to Picton. In 1907, the bridge was made even stronger. Workers added more supports and extra girders to help it carry heavier trains.
Why the Bridge Was Built High
When John Whitton was planning the railway line to Picton, the government wanted him to save money. At first, a simpler, lower bridge made of timber was suggested. This would have been about 151 metres (495 feet) long.
However, a huge flood happened in 1860. The water rose about 18.3 metres (60 feet) above where the railway was planned. This made Whitton change his mind. He decided to design a much higher bridge with large spans. This would let a lot of water pass underneath during floods.
The new design included a main iron bridge and long timber sections leading up to it. The whole structure was about 582 metres (1,909 feet) long! It was a massive project for its time.
Shipping and Construction
The main iron parts of the bridge were made in England and shipped to Sydney. One ship arrived in April 1862. Sadly, another ship carrying parts was wrecked. But new iron parts were quickly sent and arrived in Sydney by December 1862.
Workers used sandstone from local quarries to build the bridge's supports. These stone parts were finished by October 1862. The iron bridge was then put together and ready by June 1863.
To make sure it was safe, they tested the bridge with three full-steam locomotives. After passing the test, the railway line to Picton opened on 1 July 1863.
A Special Design
The way this bridge was built was very advanced for its time. It used a "continuous superstructure" design. This means the main iron beams were one long piece across all three sections, not separate pieces. This design made the bridge much stronger.
The Menangle Bridge has a "sister" bridge called the Victoria Bridge. It crosses the Nepean River at Penrith. Both bridges were so impressive that they were featured in an international book about bridges in 1872!
How the Bridge Looks Today
The Menangle Bridge originally had three large sections, each about 49.4 metres (162 feet) long. In 1907, new piers (supports) were added in the middle of these sections. Now, the bridge has six shorter sections, each about 24.2 metres (79 feet) long. These new supports are made of brick, while the original ones are stone.
The main part of the bridge is made of two huge wrought iron "box" girders. These girders are like long, strong boxes. They are about 3.8 metres (12 feet) deep and are spaced 7.8 metres (26 feet) apart. This space allows for two railway tracks to run between them. The tracks sit on smaller beams that go across the main girders.
If you look closely, you might see curved iron shapes on the outside of the girders. These look like arches, but they are just for decoration. The bridge's strength comes from its girder design, not from an arch.
In 1976, a train accident damaged one of the decorative tops of a stone pier. The iron bridge itself was only slightly damaged. However, the stone part was not replaced. This means you can now see the inside "box" shape of the girder at that spot.
Bridge Condition and Changes
The Menangle Bridge is in good physical condition. Even with the changes made in 1907, most of its original parts are still there.
The biggest change was adding the intermediate piers in 1907. This made the original sections half as long, which greatly increased how much weight the bridge could carry. That's why it can still handle modern, heavy, and fast trains today!
The original bridge also had long timber sections leading up to it. These were replaced with steel beams in 1923.
In 2003, the bridge was closed for a month for repairs. When it reopened, trains had to go slowly, at 20 km/h (12 mph). This speed limit was later increased to 40 km/h (25 mph). In 2005, it went up to 80 km/h (50 mph), and by 2013, trains could cross at the maximum line speed.
Why the Bridge is Important
The Menangle Railway Bridge is one of Australia's most historic bridges. Here's why it's so special:
- It was the first large iron bridge in New South Wales. It was the biggest bridge until the Hawkesbury River railway bridge was built in 1889.
- It looks very impressive in the countryside around it.
- It has played a huge part in the social and business growth of southern New South Wales for over 140 years.
- Its design was very advanced for its time, and it was even recognized internationally in 1872.
The Menangle Bridge and the Victoria Bridge at Penrith are the only bridges of their kind in New South Wales. They are great examples of strong, wrought iron girder bridges that are continuous over three sections. Even with the added supports in 1907, the Menangle Bridge still has most of its original parts from 1863.
This bridge is the oldest working bridge on the state's railway system. It shows how railway technology developed in New South Wales. It's also a good example of early bridge building. The iron parts were imported from Britain, showing the engineering style of the 1860s. It's so unique that there are few similar bridges still in use in the United Kingdom.
The Menangle Railway Bridge was added to the New South Wales State Heritage Register on 2 April 1999.
Historical Significance
The 1863 Menangle Railway Bridge is important because it shows the history of New South Wales. It was the first big iron bridge in the state and the largest until the Hawkesbury River Bridge was built.
Design and Beauty
The bridge has a strong and beautiful look in the rural landscape.
Community Connection
The Main South Railway has brought huge benefits to the people and businesses in southern New South Wales for 140 years. This bridge, being part of the original railway, shares in that important history.
Learning from the Bridge
The bridge's 3-span continuous girder design was very clever for the 1860s. It was even written about in an international textbook in 1872. Its "cellular construction" (where the top and bottom parts are like boxes) was a new idea to make girders stronger.
Rarity of the Bridge
The Menangle and Victoria Bridges are the only ones of their kind in New South Wales. This makes them very rare.
Example of Engineering
These two bridges are excellent examples of strong, wrought iron girder bridges that are continuous over three sections.
Engineering Award
The Menangle Bridge has received an Engineering Heritage Marker from Engineers Australia. This award recognizes its importance in engineering history.
