Please explain what is the difference between the closed tunnels and the older Clifton Tunnel still in service?The original single line alignment from Waterfall to Coalcliff was shorter (but not without some sharp curves). There were a number of tunnels: Waterfall, Cawleys, Helensbugh, Metropolitan (so named for the nearby colliery), Lillyvale Nos.1&2, and the infamous Otford Tunnel, (Google it). Increasing traffic brought the need for double track, and as in so many other places in NSW in conjunction with double tracking, they introduced a lessser graded but longer more circuitous alignment which enabled the steam power of the day to haul more economical loads. The all still in use double track tunnels are: Helensburgh, Metropolitan, Lilyvale, Bald Hill, and Stanwell Creek Nos.1&2. Today, as you drive along Lawrence Hargrave Drive between Stanwell Park and Coalcliff, you are driving on the old formation.
The original and still in use Clifton Tunnel is immediately South of Coalcliff. The Clifton Tunnel is not without its trials. It was a tight fit for the 57 class, the length of the 60 class made bad conditions even worse for enginemen, and the hill that the tunnel pierces is slowly but surely falling into the sea. All the existing tunnels had their floors lowered during electrification works and the Clifton Tunnel had extensive rectification to straighten and level it again.
I remember my father telling me that Uncle Sam wanted to blow the hill into the sea during WW2 and build a new road and railway through the resultant modified landscape, (I've never checked the bona fides of the story).
Thanks for this, obviously for sparks its a different story.
Yes I've read up on these tunnels many times, mostly counteracting Sim's random claims.
I know the old tunnels won't be reused because they won't have full length access side platforms for emergencies and I think this is the main issue overall. Dropping the floor to increase clearances is not a drama, its been done many times across Australia, easier if the tunnel is not in operation. Realistically the boring costs for a single track tunnel are not that expensive. For this project you could build a pair of twin tunnels for a few billion as no stations apart from maybe Helensburg. So just drop a TBM at the end and let it run for 12mths to the other end, no costly stations and other infrastructure to deal with. How to do the South Coast without Gold Plating it into a over priced HSR.
The tunnelled route is about the same length as NWRL tunnel so with only one station and simply connecting the two ends no Sky rail section, rail depo and ECRL conversion, it will be alot less than the NWRL's $6B cost, likely $2-2.5B. Build the tunnels Electric traction only (save cost) and leave the oil burners on the current corridor.
Most of the stations on the current route that would be by-passed are all within a short drive, in some cases walk of each other due to the rails alignment and for the numbers are not worth maintaining in operation with the new corridor especially if Helensburg is kept and potentially centralised in the town.
All stoppers do Scarsborough to Waterfall in 30min, the new tunnelled option would do it at say average 120km/h in 7-8min, lets say 10min with a station stop to call it even. 20min saving.
North of Sutherland, the corridor is wide and reasonably aligned and begging for Quadding and higher speed running. Jannali station is the only hard part. Como statio looks fairly easy.
Then we have the bridge, you can go cheap and use existing (I wouldn't argue for that for a cost reduction option)
North of the river, there is what appears a potential corridor east of the existing tracks bypassing Oatley station but running through the Mortdale carriage wash. So diver down just prior and start a 4.5km long tunnel to Kingston station. $1 - 1.5B.
As I stated before, Mortdale to Kingston diversion and on express Quads to Wolli Creek, saves alot of time and prevents the need for more costly Quading south of Hurtsville. The current time table Sutherland to Wolli Crk is 20min for 15km (45km/h), potentially the above would drop down closer to 10min depending on track speed.
So all up
- Saved say 30min of 90min timetable,
- Cost around $5-6B.
- Enabled significant increase in frequency
- Reduced congestion for freights.
- Allows more Cronulla/Waterfall services
- Reduce operating cost for NSW trains as each set does the round trip to Wollongong in 1h less, so for efficient use of rolling stock and staff effectively increasing the size of the fleet