North of Bungendore, the line encounters rolling countryside with a few substantial hills that must ideally be avoided. There are fewer sections of the existing alignment with minimum radius under 1000m (the smallest radius at which 200km/h is possible with tilting trains). We are therefore able to use the existing alignment more frequently. We will also however identify potential future corridors that would allow very high speed transit (>300km/h), and attempt to design the Hot Rails alignment such that a minimum of the proposed construction would be made obsolete in such a scenario.

There is a 45° turn of approximate radius 240m immediately after Bungendore Station. It is difficult to increase this radius significantly; 1000m is possible only with the acquisition of several properties, and an unorthodox station siding layout. Any substantially greater radius will require bypassing Bungendore altogether; this is not desirable as Bungendore is a major satellite community of Canberra.

Alignment Design

Bungendore to Mt Fairy plan – click to enlarge

Summary

The total cost of the sector is $80.6 million, averaging $5.2m/km. As expected, the lower length of new alignment results in drastically lower capital costs per-kilometre. The largest contributors to this cost (other than track, which is non-negotiable) are the substantial earthworks needed for the Butmaroo and Mount Fairy deviations. The route here could be varied slightly to minimise earthworks, but the savings are not likely to be substantial. Except for the curve within Bungendore, radius has been raised to 1500m, so the maximum speeds allowable on this sector would be 250km/h with tilting trains, or 200km/h with non-tilting trains. The curve near Bungendore Station is restricted to a radius of 1000m due to existing development, which will result in allowable speeds of 200km/h for tilt trains, or 170km/h for non-tilt trains.

[table]
Component,Cost ($m),Percentage
Bridge,5.7,7.0%
Earthworks,24.5,30.4%
Track,33.6,41.7%
Signalling & Control,6.0,7.4%
Civil Works,8.5,10.5%
Land,2.4,2.9%
TOTAL,80.6,100%
[/table]

Turallo Creek crossing

Section length 800m, sector start. The existing curve must be eased to the exceptional minimum radius of 1000m; to achieve this, several properties on the eastern side of Powell St will have to be acquired and demolished (1500m radius would be possible, but only with the acquisition of many more properties, perhaps another 10). According to a Realestate.com.au suburb profile, the median house price in Bungendore is currently $585,000 (January 2015). The houses are a couple of metres above the existing alignment, so a small cut is required here. A second Turallo Creek bridge will need to be built; a plausible design would be a single 40m span with embankment approaches. The new track will not have direct access to the platform at Bungendore Station; therefore, the existing track will be retained as a passing loop and for all-stops services to access the existing station infrastructure. Express services will bypass the station a few metres to the east of the existing through-track.

1000m radius curve within Bungendore. Houses to be acquired in red.

• Bridge
  • Cost function = 11725e^0.012*40
  • $18,949/track-m, 2.35x multiplier for single span
  • Total cost = $3,562,000
• Earthworks
  • Balanced cut/fill: 500m @ 2m depth
  • 14,000m3, = $210,000
• Track
  • New dual track @$2.25m/km = $1,800,000
  • Upgrade existing single track = $800,000
  • 2x low speed turnouts = $1,400,000
• Signalling and Control
  • 1 turnout signal = $4,000,000
  • Cable and balises = $102,000
• Civil works
  • Drainage = $160,000
  • Steel palisade fencing = $80,000
• Land
  • 5 houses must be acquired.
  • Total cost $2,925,000

Bungendore exit

Section length 7950m, starting at 800m. This sector utilises the existing corridor the whole way, except for a very minor deviation at the second curve (which has radius 800m – the others are 1500m). Several sections of cut and fill will need to be widened. We will assume a complete replacement of the 50m-long Butmaroo Creek bridge, with a mainspan of 20m. The farm crossing at Butmaroo Halt must be replaced by an overpass due to terrain.

• Bridges
  • 2x small culvert crossings: $200k each
  • Butmaroo Creek bridge: 50m with 3 spans
    • Cost $1,714,000
• Earthworks
  • 2km fill widening, approx. 3m avg. height
  • 500m cut (rock), avg. depth 5m
  • 2.5km cut widening (non-rock), avg depth 5m
  • 400m bridge approach fill widening: avg depth 4m
  • 650m cut widening, avg depth 4m
  • Total cost: $4,856,000
• Track
  • Upgrade 1, add 1: 6.95km
    • $13,031,000
  • New dual: 1km
    • $2,250,000
• Signalling and Control: $1,010,000
• Civil Works
  • Chainlink fence (both sides): $795,000
  • Drainage: $1,590,000
  • 1x minor overpass: $1.25m
• Land: 40m corridor for 1km, high quality farmland
  • 4ha @ $10,000/ha (conservative) = $40,000

Butmaroo deviation

Section length 3520m, starting at 8750m. Leaving the existing alignment at the curve shortly after Butmaroo Halt, the 600m-radius Butmaroo curves are replaced by a single, R3000m curve which rejoins the existing corridor at the summit. The existing alignment in this section follows a gradient of 2.5%; as the new alignment is shorter, the gradient must be increased to 3% for a distance of about 2.5km. A gradient change from +3% to -1% occurs during the curve over a distance of about 1.5km, which is within the desirable range for vertical profile.

A series of cut and fill sections will be required to achieve the new alignment, the deepest about 20m. Assume a 60-m wide corridor must be acquired along the entire section. The land consists mainly of a mixture of small, high quality farmland and bushland; conservatively assume an acquisition cost of $10,000/ha for the entire length.

• Earthworks
  • 2.2km fill, avg. height 7m
    • 422,400m3, $6,758,000
  • 1.2km cut widening, avg. depth 10m
    • 144,000m3, $4,464,000
• Track: $7,920,000
• Signalling and Control: $447,000
• Civil works
  • Chainlink fence (both sides): $352,000
  • Drainage: $704,000
  • Farm underpasse: $500k
• Land: Assume 60m corridor due to width of earthworks
  • $211,000

Mt Fairy approach

Section length 3180m, starting at 12270m. Immediately after the Butmaroo deviation, a new deviation eases the radius of the curve near Sandhills Road from about 400m to 1500m. The existing alignment is then rejoined 2km prior to Mt Fairy Halt.A 60m corridor will need to be acquired prior to rejoining the existing corridor; current prices on realestate.com.au indicate a cost per hectare of $10-$15k, including houses.

• Earthworks
  • 1.9km fill, avg. height 5m
    • 185,250m3, $2,964,000
  • 1.0km cut, avg. depth 8m
    • 160,000m3, $4,960,000
  • 1km fill widening, avg. height 3m
    • 18,000m3, $288,000
• Track
  • 1180m new dual track:
  • 2000m upgraded and duplicated:
• Signalling and Control:
• Civil works
  • Chainlink fence: $318,000
  • Drainage: $636,000
  • 4x farm underpasses @ $500k each
• Land: assume $10,000/ha
  • $70,800