General civil works refers to all the incidental stuff that needs to be built in order to make the alignment safe, low maintenance, and with minimal impact on other transport corridors or existing development. We will include the following items in this category:
- Safety barriers
- Retaining walls
- Noise attenuation walls
- Utilities relocation
- Site clearance and minor demolition
AECOM13 will be used for the majority of the cost items, but augmented with other sources where costs refer to extremely over-designed works, or are not included in the HSR study.
It is plausible that the placement of new rail alignment, or the widening of existing alignment, would require the relocation of existing roads, and such it will be included for Hot Rails. Additionally, it is helpful to know the cost of road surfacing to estimate the total cost of bridge structures.
Road cost is highly dependent on the class of road being built. Main Roads Western Australia (2003) suggests typical construction costs as follows (cost data converted to 2013 AUD per lane-km):
- Local road: $83,245
- Rural main road: $129,596
- Rural highway: $870,774
- Freeway: $970,877
The Florida Department of Transport‘s numbers are similar; 2014 data, converted from $/mile to $/km (NOTE: per route-km, not per lane-km!)
- 2-lane rural road: $1,270,000/km
- 4-lane rural road: $1,895,000/km
- 6-lane rural interstate: $3,665,000/km
The European Concrete Paving Association estimates the cost of a 11.05m wide (2 lane) concrete motorway to be €1,165,000/km (AU$828,000 per lane-metre), and an equivalent asphalt highway €909,000/km (AU$646,000 per lane-metre).
Given the above cost data, the following are considered conservative estimates for greenfield construction cost:
|Rural main road||$500000|
Roadworks was not a cost category that was investigated in AECOM13; the only mention of roads are “minor access roads” (ie, maintenance tracks), costed at $1.5 million per kilometre. This is yet another example of the absurdly expensive estimates AECOM13 has taken; assuming this refers to twin, single-lane access tracks as specified in the “typical cross section”, it means the access tracks cost $750,000/lane-km, which is highway grade. It adds up to well north of a billion dollars over the total distance.
AECOM13 costs fencing at $90,000/route-km (rural), and $200,000/route-km (urban). Presumably this refers to fencing on either side of the track, so the numbers can be halved to obtain fence-km costs. $45,000 per fence-km is not an unreasonable cost for chain-link (“Cyclone”) fencing (see example from Canada, or price estimation brochures from profence.com.au and Preston Fencing, UK).
However, it is open to discussion whether or not such a fence is necessary in rural areas; the existing Sydney-Melbourne XPT line is mostly fenced with standard livestock fencing, which costs upwards of $10,000/km (ref: Built a fence myself a couple of years ago). A study for the Brisbane Valley Rail Trail costed agricultural plainwire fencing (including gates, etc) at $14,000/km. Most agricultural fencing is a mixture of ringlock mesh, plainwire and barb wire, so the actual cost is likely to be somewhat higher, say $15,000/fence-km.
The Minnesota DOT has several cost estimates for fencing (adapted to $/fence-km), installation costs included:
- 4 ft woven wire: $18,125
- 6 ft chain-link: $53,726
- 10 ft chain-link: $61,490
- “Decorative” fencing: $138,509
For urban fencing, AECOM13’s cost of $100,000/fence-km probably refers to a solid “steel pallisade” type security fence. This is considered a plausible estimate. However it is probably un-necessary to include such a heavy-duty fence in all urban situations; a chain-link security fence with 3 strands of barbed wire at the top is effective in many situations. This type of fence is substantially more expensive than the standard chain-link fence – an estimate of $75,000/km is reasonable.
|Chain-link (6ft plain)||$50000|
|Chain-link (8ft security)||$75000|
|Steel pallisade (8ft security)||$100000|
AECOM13 does not include estimates for concrete or steel safety barriers. Hot Rails intends to substantially re-use existing rail corridors, possibly also highway corridors, for which safety barriers will be essential. A 2007 report for the Alberta Department of Infrastructure and Transportation estimated the cost of steel W-section barriers (often referred to by the genericised trademark Armco) to range between $90 and $300 per metre in 2007 CAD ($114 – $380 in 2013 AUD). The same study also estimated the cost of pre-cast concrete barriers at between $275 and $345 per metre (AU$349 – $438 in 2013). However, the Australian College of Road Safety in 2003 suggested a substantially lower figure, of $85/m for steel and $102/m for concrete barriers ($111 and $134 in 2013, respectively). The California DOT in 2001 priced steel W-beam at $61/m and concrete barrier at $150/m ($158 and $388 AUD in 2013, although recall that 2001 was an exceptionally bad year for the Aussie dollar). More recently, in 2011 the USDA estimated the cost of concrete barriers (installed) at about $60/foot (about $212/m in 2013 AUD). Several manufacturers have pricing for individual pre-cast barriers available online, which usually works out at slightly less than $200 per metre (retail).
This is an extremely wide range of estimated values; conservatively taking the higher end of the range, Hot Rails will assume $150/m for steel barriers, and $350/m for concrete barriers.
Under some circumstances (such as in urban areas where space is limited) it may be necessary to limit the width of any cutting or embankment. In this case, retaining walls can be used. AECOM13 has estimates for several classes of retaining wall, which average $2,500/m2. This can obviously add up quickly; a 3m-high retaining wall ends up costing $7.5 million per kilometre – $15 million per kilometre if you have to put it on both sides. It is very difficult to come up with an accurate estimate of the area needed without detailed engineering drawings.
Fortunately the need for retaining walls will typically be limited to short sections in urban and suburban areas.
AECOM13 estimates longitudinal drainage at $475,000/km, and cross-drainage at $390,000/km, for a total of $865,000/km. This strikes me as somewhat on the high side, but without any specification of the longitudinal drain, or how many cross-drains per kilometre, it is difficult to assess its plausibility. Let’s look at some other estimates.
The Minnesota DOT provides a drastically lower estimate: $75,000 per mile ($46,500/km) for new installation of 30″ diameter longitudinal drainage pipes along both sides of the alignment. That’s a phenomenal difference – the AECOM estimate is over 10 times higher! So which is closer to reality?
Recall that a 2-lane rural highway would cost somewhere between $250,000 and $1,200,000 per km to build (depending on which source you believe), but in any case, $865,000 would represent a large percentage of it. Now ask yourself: Is drainage a large or a small percentage of total highway construction cost?
The Florida DOT has a great series of documents which estimate the cost of road and highway construction based on individual component costs – which includes drainage. Costs relating to concrete pipe culverts for cross-drainage total $157,000/mile (approximately 373 linear metres of 24″ concrete pipe, plus 40 mitred end-sections). This converts to about $97,500/km. Also, the need for 40 end-pieces implies 20 culverts per mile, or one per 80 metres. The 373 linear metres in total implies that each one averages about 18.6m in length, which is pretty much exactly what we would expect for a 2-lane highway.
In short, $865,000/km for drainage is not remotely supported by available cost estimates. Using the Minnesota data for longitudinal drainage, and the Florida data for cross-drainage, we have a total cost of about $144,000/km. Although I am unsure why longitudinal drainage is necessary when it does not appear to be installed on any existing rural railways or highways, both longitudinal and cross drainage will be specified for Hot Rails. Applying a reasonable premium of 35% for Australian construction costs compared to the USA, the cost for drainage is assumed to be $200,000/km for all new alignment (excluding bridge and tunnel structures, for which drainage is included in the cost).
Noise Attenuation Walls
$4.8m/km (rural) and $9.5m/km (urban) is assumed in AECOM13 for noise attenuation walls. This again seems high, but a brief review of some past projects suggests that the cost is plausible. However, it should not be necessary to install such barriers in all but the most unusual circumstances – most existing railways transit residential areas – often passing within tens of metres of houses – with barely any length having sound attenuation walls.
Hot Rails will generally not specify the construction of noise attenuation walls, except where a proposed new alignment must pass within 50 metres of an existing residential area.
Grade-separated crossings were included in the “Bridges” category of AECOM13. Hot Rails will categorise them as civil works, since they are not actually part of the railway alignment itself. We will also include level-crossings. Level crossings were not included in AECOM13 at all, because at a design speed of 400km/h, all crossings must be grade-separated. 200km/h is still very fast, but some jurisdictions do allow level crossings to be traversed at comparable speeds. For example, Sweden and the United States both allow speeds of 200km/h through gated level crossings. For passive or lights-only level crossings, Norway allows a speed-limit of 160km/h, the USA 110mph (177km/h), and Australia 160km/h (the XPT lines still have many farm crossings marked with nothing more than a “watch for trains” sign).
There are three types of level crossings:
- Passive – warning signs only, plus concrete road surface treatment.
- 2010 Inland Rail Alignment Study assumes cost of $120,000 each. Presume most of this cost is associated with the concrete road treatment and approach roadworks. Also, the IRAS was for a single track. Assume 1.5x for double track, so $180,000 each.
- Active Lighted – Addition of automated lights and bells.
- Active gated – warning signs, lights, bells and boom gates.
- IRAS assumes $900,000 each (refers to generic “Active” crossing – assumed to refer to gated crossings due to low cost of lighted crossings)
- Kiwi Rail assumes NZ$200,000 upgrade cost (AU$180,000), meaning a total cost of $300,000.
- The Minnesota DOT (2011) estimates a cost of US$326,000 for a four-quadrant gated crossing, or US$556,000 with trapped-vehicle detector.
- The IRAS estimate seems very high when compared with other estimates. Conservatively assume cost of $700,000 each.
AECOM13 prices three types of grade-separation: Road-over-rail and rail-over-road are both assumed to cost $5 million each (including approaches), while minor underpasses and farm crossings are priced at $2.5 million each. It assumed a frequency of farm crossings to be one per 2km in rural areas.
The Inland Rail study separated crossings into “major” (4 lane) and “minor” (2 lane), both including approaches of 300m on each end. The assumed cost was $5.626 million for major crossings, and $4.722 million for minor crossings.
Kiwi Rail agrees with the above, suggesting a generic grade separation would cost upwards of NZ$5 million.
$5 million seems to be a widely-agreed number, but it still does seem very high. $2.5 million for a farm crossing is outrageous – a box-culvert big enough for a Hilux would be fine in 99% of cases. Consider the bridge replacement program of Palerang Council in southern NSW, where a basic box-culvert bridge (which looks like it would be suitable as a basic farm underpass with minor modifications) was recently constructed for a mere $500,000, and a more complex concrete beam bridge over the Molonglo River is forecast to cost $1.2 million. Further studies confirm a low cost for farm underpasses; they were costed at $300,000 each in the 1990 VFT report ($540,000 in 2013), and an early draft of the 2010 IRAS study costed 5.05 x 4.2m box culverts at $177,000 each (single track, assume $354,000 for dual-track). A Hilux is well under 2m in width, meaning this would be more than adequate, and possibly even adequate for minor public roads. An estimate of $0.5m each is reasonable.
However, in my opinion the strategy of assuming a constant cost for grade separations is flawed from the beginning. Like all bridge structures, the cost of construction is highly dependent upon the individual geography of each location. A crossing where the railway is already in a deep cutting may require only the most basic of beam-bridges, but a skew-crossing where the railway is elevated on culverts in a floodplain may require a much longer span bridge with complicated pylons and long embanked approaches. The bridge cost functions developed by Hot Rails will assist in making ROM costings of bridges based on individual situations. However, where this is deemed too difficult, Hot rails will assume the following:
|Crossing type||Estimated cost (AUD)|
|Minor grade separation (simple)||$1.25m|
|Minor grade separation (complex)||$2.5m|
|Major grade separation||$5m|
Site Clearance and Minor Demolition
Hot Rails will use the AECOM13 assumption of $125,000/km for all areas where minor demolition is required.
Hot Rails will use the AECOM13 assumption of $125,000/km (rural) and $575,000/km (urban) in areas where proposed new alignment will impact existing utilities.
AECOM13 assumes a substantial cost for an undefined metric of “slope stability”, ie, prevention of erosion on cuts and fills. Their numbers are $2.16m/km for slopes under 30° and $5.78m/km for slopes over 30°. Slope stabilisation strategies are, in my opinion, completely unnecessary. Look at any cutting along the Hume Highway, or any of the fills on the Canberra railway, or just about any infrastructure project not built in the last five years. There’s not a shred of “slope stabilisation” to be seen. Bare rock has been good enough for the vertical sandstone cuttings of the Sydney-Melbourne railway for a hundred years, and I don’t see why that needs to change now. Where erosion is a genuine concern, grass is a much more aesthetically pleasing and equally effective alternative than the over-engineered solutions currently in fashion, and that sure won’t cost a million bucks a kilometre.
Hot Rails will not assume any cost for slope stability. Grassed fill or bare rock cut is perfectly fine as far as I’m concerned.