Friday, 11 September 2020

Western Bridges

For some time I have been following the upgrading of bridges in South Western and Central Queensland Darr River is located approximately 33 km north west of Longreach near Morella. The bridge was damage during flooding in February 2012 and collapsed under a ballast train, the hauling locomotive made it to the other side without injury to the crew. The bridge was repaired and reopened in July.
April 2013 A contract to VEC Civil Engineering Pty Ltd for $ 1.33 million saw the bridge replaced and open to traffic on the 20th Arial 2015. The VEC construction crew battled temperatures in excess of 43 degrees Celcius. A Cultural Heritage Induction taught the crew how to find artefacts and how to report it correctly to Queensland Rail if some artefacts are found on the site. This bridge is higher than 6m and when working outside the handrails, and thus required the crew to be hooked up with the harness and apply working at heights rules and regulations. The VEC selected design allowed for the ease of substructure construction between trains and for a 60 day possession period to demolish the existing superstructure and piers, place the new crossheads packers and superstructure before re-connecting the rail and re-opening to rail traffic. I was in the area in during April 2016 and the new bridge was complete and the water hole was dry under the bridge. What a great opportunity to check out new constructions methods.
Being out in Longreach (Aug 20), it was time to check out the bridge again. This time the weekly Winton to Rockhampton freight service crossed the bridge. The train would pick up another 5 similar wagons at Longreach and two at Alpha. Like most things over time things change, likewise our railways. At first trains were steam hauled, then diesel. Wooden wagons were replaced with steel. Structures also changed over time. During the mid 1990’s, QR upgraded a number of lines from “B” class (10t, some were 12.2t axle load) to “A” class (15.75t). “B” class lines were restricted to 63t locomotives (1700/1720 class DEL), many were in need of overhaul. The upgrade allowed a wider use of the 93 t locomotives. Upgrading of the lines include strengthen the bridges.
1701 crosses Angellala Creek at Angellala (Morven – Charleville) in the mid 1980’s. At the time the line was “B” class with an axle load of 12.2 t. To allow 93 t DEL’s to cross over Angellala Creek, a new sub frame was constructed under the iron section of the bridge.
The timber trestle section of the bridge didn’t require muck work. When looking at some of the trestle bridges on the Longreach to Winton section, some additional timbers were required. The Darr River overflow highlights extra piers and supports were used.
My last visit to the bridge in August 2020 I found the bridge had been upgraded.
New bridges and other work done on bridges on the line, has not done much in increasing trains speeds. Hardly, competition for road transport with a highway speed of 110 Km/h..
Timber bridges on older “A” class lines have much more to them.
Cooranga Creek Warra. For us modellers, bridges over flood plains we have endless choice, some have simple structures.
Spirit of the Outback, 671.271 KM near Longreach. August 2020. “A” class line
Cunnamulla Line near Westgate. "B" class Line. If you are a era modeller, the photos highlights how structures change over time.
Awesome bridge scene on Bob Harding Layout “Mosquito Creek”

No comments:

Post a comment