Tuesday, 9 December 2014

Hawkswood Overbridge (Main North Line)

The first image below is a frame from a video shot by a tourist who attached a GoPro type camera to a locomotive (as far as I can tell).
Just before the overbridge on SH1 we can see to the left and right the remains of the concrete abutments of the old overbridge here. This started out as a one lane concrete structure, probably in the 1930s or perhaps earlier as the exact date the railway north of Parnassus was built is not clear (it was not opened until 1939, to Hundalee). 
This map shows the changes in the highway including with the overbridge.
In this map we can see the old section of highway north of the bridge. It consists of several sections:
  • The approach to the bridge from the south involved a short sharply curved section immediately west of the highway.
  • After crossing the bridge, Hawkswood Road descended on a zigzag to cross the Hawkswood Stream at a low level, to the east (the bridge was called the Cold Stream Bridge). This section is still used as a local road. On the present highway, Hawkswood Stream is crossed just north of the overbridge, by a culvert, which appears also to be the way the railway crosses it.
  • The road then climbed again and crossed over the present road heading towards Ferniehurst. A section of the old road is still in use as the access to Ferniehurst Railway Station, including the bridge over Chilly Stream.
  • The road then crossed over the present alignment again and finally met the current alignment again at Siberia Ford. This was an actual ford which is now bridged.
The highway realignments were two separate sections (Hawkswood and Ferniehurst-Siberia) and were built between 1999 and 2001.
This is the old section of the highway (Hawkswood Road) with the road going down and right to the bridge then climbing back up on the far side to the left before reversing again and going to the right. The hairpin bend was a 35 km/h curve.
What is surprising about all of this is much larger trucks today are rated to go on the much worse highway over the Hundalee Hills without any thought of fixing up the highway at all.
The video clip below is the actual clip from Youtube that was used to grab the frame above.