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Tunnelling specialists have welcomed proposals to build a new rail tunnel crossing below the Firth of Forth in Scotland as part of plans put forward by the Scottish Green Party to improve the rail network and deliver on carbon net zero transport promises.
The Rail for All plan, published earlier this week, proposes a 14.5km long twin bore rail tunnel is driven under the Firth of Forth from Abbeyhill to Seafield, between Kinghorn and Kirkcaldy, passing under Leith. The tunnel proposal is claimed to be essential to easing the bottleneck around Edinburgh’s Haymarket Station, which “affects the whole network”.
The Scottish Green Party has suggested the cost of the tunnel to be in the region of £4bn to £6bn and tunnelling experts have suggested that the project could be delivered in five to seven years, if funding was secured.
According to LBA chair Martin Knights, studies carried out in the mid-2000s for the new Forth road crossing considered a tunnelled option and he believes that the solution is technically possible.
“While not without hydrographical and geological risks from carboniferous and volcanic formations, dykes, faults and varying profile of sea bed and rockhead, recent subaqueous tunnelling projects in the UK and Nordic Countries have demonstrated that tunnelling of this nature is entirely feasible,” he said.
“This is demonstrated by the spectacular advances in tunnel boring machine and blasting technology for hard rock and variable ground conditions. These advances in tunnelling technology make it possible to consider undersea transit crossings such as the UK government`s current Union Connectivity initiative, chaired by Sir Peter Hendy, between Northern Ireland and Scotland.”
Knights also points to work in Norway and Japan for how advances in tunnelling capability are already delivering deep sea tunnel schemes.
Another tunnelling specialist, who asked not to be named, added: "Long tunnelled sea crossings both by Immersed Tube and bored tunnels are feasible. The bored tunnel proposed would pass through Carboniferous rocks, some of which have been mined for coal, which would pose a challenge."
The Scottish Government confirmed that a Forth rail tunnel was considered in 2007 as part of the study that led to the construction of the Queensferry Crossing. At the time the government concluded that increasing capacity on the Forth Bridge for long trains combined with timetable improvements was a more cost effective way to boost capacity.
Dr Sauer & Partners managing director Brian Lyons agrees with Knights with regard to the feasibility of the project. “Although the Firth of Forth is historically more associated with bridge crossings, the alluvial deposits and bedrock likely to be encountered across the estuary can be managed by modern bored tunnelling techniques as demonstrated on major crossings of the River Thames in recent years,” he added.
“The UK tunnelling industry has the skills and capacity to deliver this project within a timeline of five to seven years.
“Key challenges for the new link are likely to be related to environmental concerns such as contaminated land, habitat etc and planning issues including potential legal challenges to the proposal. Other key technical issues will include integration of ‘new and old’ at locations where the new infrastructure and rail systems link to the existing rail network.”
Knights also urges more studies to be undertaken to “quantify and confirm the feasibility in terms of cost, programme, delivery and risk”.
According to the report's authors the project could be transformative. Deltix associate David Prescott, who co-wrote the report with David Spaven, for the Scottish Green Party said: “At a stroke, the Forth tunnel can transform the geography of Scotland, just as the Forth Bridge did 130 years ago and the Forth Road Bridge nearly 60 years ago.
"It would substantially cut the distance between Edinburgh and east Fife, Dundee, Aberdeen, Perth and Inverness, whilst also putting Leith at the heart of the Scottish rail network.
"The Forth tunnel would give this generation of Scottish engineers the opportunity to continue the strong traditions of their illustrious predecessors – creating transformational infrastructure for the nation.”
A spokesperson for the Scottish Government did not rule out the project but said: "Aspirational projects, such as the Firth of Forth tunnel, would be subject to the same scrutiny from the earliest stages to ensure they merited any serious consideration.”
The Scottish Government is expected to publish its Strategic Transport Projects Review next month, which will set out major projects planned for the next 20 years.
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Err, BRAIN.
Benefits – not enough for a sufficient number of people
Risks – opportunity cost aside from construction risk
Alternatives – many much needed phased built high speed line upgrades (cf Denmark/Sweden)
Instincts – does it really look beneficial to 5.5m Scots’ -> no.
Nothing – yes please, and think again.
Scotland’s three largest cities are unconnected by high speed rail, and the two most expensive transport assets, Glasgow and Edinburgh Airport remain unconnected directly to any rail line, never mind a high speed rail line. Similarly, the closest major English city, Newcastle, is at best still 2.5hrs from Glasgow and around 1.5hrs from Newcastle. ALL unconnected by high speed rail, with no plans to do so either.
So of course this tunnel is technically feasible, but even greater time savings can be made by investment in other areas of the Scottish network for less which will benefit more people, including for travellers from Glasgow to the NE, as well as Edinburgh to the NE, or to Newcastle on an HS2 extension from Newcastle to Scotland. It’s not how much you spend, but how you best use the money, but this tunnel definitely isn’t it.
The complete Scottish Green plan is £22bn, so for around £4000 per Scottish person (pop 5.5m), or £8660 per working Scottish tax payer (=2.54m). Just the £4-6bn for their Forth Tunnel could instead pay for much of the track and tunnels through the Borders and Pentlands on route D in the 2016 HS2 “Options from the North of England and Scotland” report, which would provide sub ONE hour journeys between Glasgow & Edinburgh to Newcastle.
The £4-6bn tunnel is a very poor choice of route for investment spending:
– Their tunnel misses out a heavy rail connection with Edinburgh Airport which could become a transport hub. We know the Greens hate aviation, so much so they blanked it in this £22bn programme, but it isn’t going away, it is better to connect environmentally friendly transport to the airport and the airport plugged into a national rail network to help reduce aviation, not pretend it doesn’t exist, eg like the ongoing underground tunnel station for Stuttgart airport. Note rail is okay for the Greens, but high speed rail (which would take drivers from polluting cars and passengers from polluting planes) isn’t, comical if it weren’t so serious an omission and when the power for very high speed trains will come increasingly from wind energy or other environmentally friendly sources.
– Connects into Waverley in the wrong direction to all other through services on the East Coast Main Line as has traditionally done. So inefficiently misses out Edinburgh Waverley station on all services from Aberdeen to London reducing your choice of train option if you want to get off at Edinburgh or between Edinburgh and Dundee.
What they should be proposing:
The recent Portuguese Government plan to build a 200 mile long, 300/320kmph high speed line between Lisbon and Porto for around 5bn euro, part of a 10.5bn euro, sixteen scheme, national railway investment programme. That distance is the equivalent of a full high speed railway line between Aberdeen and 20 miles south of Berwick on the east coast, or as far as Lockerbie on the West. Scotland could get a whole 200mph line almost the length of the country for the same price as the Greens propose a twin bore tunnel across the Forth; does anyone now think this consultancy and Green plan in comparison makes them sound absolutely ridiculous?
A direct heavy rail connection to Edinburgh Airport would also be part of that plan, built at the east side of the airport on the East Coast main line to Fife & NE Scotland, replacing the significantly underused (30% of expected demand) £41m Gateway train/tram interchange – another financial failure for Edinburgh like the tram. This would create a second major multi mode transport hub on the only side of Edinburgh where development seems to be allowed. The planned Almond/Dalmeny Chord would also allow direct train access to the airport station from Glasgow Queen St. The shorter cross runway was closed to use a couple of years ago, allowing development, so this station would be like the one at Charles de Gaulle or Lyon Airports on the high speed lines. By also extending the track by just 3 miles from the new airport station, south next to the ring road and to the east side of Heriot-Watt, it would connect to existing track near Currie. That link would provide a direct connection to the West Coast main line and provide an alternative route for trains travelling between England and the north of Scotland avoiding the Haymarket “bottleneck” – not every city in Europe is so dependent on just one city station, and Edinburgh Waverley is maxed out with no plans to provide any relief tunnel station such as those built at Antwerp or Bologna.
As for a new terminal station at St Enoch, no! Any new stations in Glasgow need to be through stations as proposed in a report a year or so ago which recommended a tunnelled through station (Prof David Begg / Glasgow Connectivity Commission). The most inefficient section of any network is a terminal station. It is also possible to make an above ground through station in Glasgow between the east most old bridge piers of the Glasgow Central station access and the south side of St Enoch, but this will require some of the buildings boxed in between Jamaica St, Howard St, Dixon St, and Clyde St to be demolished. However such railways are all over German city centres, I don’t hear the complaints there, and it would be a significantly more efficient network in that it would provide Glasgow with a much needed through station.
To increase capacity and more importantly access east and west into Edinburgh Waverley, then they should be building a 2 or 4 platform underground station at Waverley. Sounds expensive, well not as expensive as the Green’s £4-6bn tunnel, when the brand new underground station at Bologna with 4 high speed train platforms cost around £400m, allowing full length high speed trains to pass through without being affected by local commuter trains. It would be ideal for Edinburgh and Scottish railway network resilience – rail users are often stuck behind broken down trains in the Haymarket tunnels. Waverley station needs resilience and backup lines which the equivalent of the Bologna high speed underground station would provide.
£135m = £2.5m per train x 54 trains – the cost of pushing UK Government to order 54 HS2 classic compatible trains with a tilt system installation. The existing £2.75bn tender order is yet to be decided, with each 250mph train costing £51m each. The cost of fitting a tilting pack to the Alstom or Talgo manufactured trains is around £2.5m. This would allow these trains to be used anywhere in the UK off of the HS2 line where overhead electrification existed, and running faster around curves and cutting journey times throughout the network where Network Rail had surveyed and fitted the inexpensive tilt approval balise transmitters. These trains would easily cut up to 20 minutes off journeys to Aberdeen on the existing track if it were electrified, and where the balise tilt activation equipment was installed (so much less than a £4bn to 6bn for a tunnel). If lines remained non-electrified then I’m sure tilt and hybrid diesel or hydrogen options will still cost billions of pounds less than the Greens’ plan.
For around £30m per km, any number of existing land based railway restrictions could be upgraded with 200mph high speed railway track which over time could form a complete high speed network within Scotland. There are so many areas on the east coast main line through the central belt, Fife and up to Aberdeen where 20-30 mile long sections could be upgraded, just the approach that has been taken in Denmark. Why don’t the Scottish Greens go away and talk to the Danish Greens – they might actually learn something:
Too many options to list, but look at the journey time savings (same or more than the Greens tunnel, for far fewer billions of pounds):
North side of Forth Bridge to south of Perth = 30 miles = £1.2bn (journey = 10 minutes @ HS2 speeds) (currently 57 minutes for Inverkeithing to Perth)
Stirling to Perth = 41 miles = £2bn (benefits all Glasgow to NE and many Edinburgh to NE train journeys) (journey = 13mins @ HS2 speeds, currently 35 minutes)
Dundee to Stonehaven = 58 miles = £2.7bn (benefits all journeys to NE) (journey = 19 mins @ HS2 speeds, currently about 55 minutes)