As a part of their plans improve the Scotland's rail network and to attain carbon net zero transport, Scottish Greens propose a tunnel which would be bored under the Firth of Forth. The proposed tunnel would have twin bored tunnels each 14.5 kilometre long..

This is what is included in Scottish Greens' report titled ''Rail for All: delivering a modern, zero-carbon rail network in Scotland’ commissioned to Deltix Transport Consulting on request from John Finnie MSP (Greens' transport spokesperson).

The whole new railway plans would cost around £22 Billion to implement and the cost of the tunnel is estimated to be in the range of £4bn to £6bn.

John Finnie says the Rail for All programme should be a central part of Scotland’s green recovery from the Covid-19 crisis.

Greens'policy briefing says:

A Firth of Forth Tunnel to transform east coast transport

The current network focuses all trains linking Edinburgh to the rest of Scotland through Haymarket, which, along with our dependency on the speed-limited Forth Bridge, creates a major bottleneck that affects the whole network. We are proposing a Firth of Forth Tunnel to ramp up capacity on east coast services and provide a fast and direct connection between Edinburgh and Fife, going on to Dundee and Aberdeen. This would reduce journey times between Edinburgh and east Fife, Dundee, Perth, Aberdeen and Inverness by 25 minutes and bring Kirkcaldy, Glenrothes, Levenmouth, north and east Fife, Perth and Dundee to within an hour of central Edinburgh. It would also massively increase capacity on the wider network and make freight transport an option between Fife, Edinburgh and the East Coast Main Line. The tunnel concept would incorporate a station at Leith, greatly improving connectivity for the c.50,000 residents of the district as well as the wider North Edinburgh area.

Rail experts Deltix advise:“Using modern technology we suggest that two 9-mile, single-bore, rail tunnels are driven under the Firth of Forth from Abbeyhill to Seafield, between Kinghorn and Kirkcaldy, passing under Leith.  These would be connected to the east end of Waverley station using the former Abbeyhill loop off the East Coast Main Line east of Calton Tunnel, with the railway burrowing underground below Leith (served by an underground station) then the Firth of Forth, returning to the surface near Seafield.

“It should be noted that there has been a long history of boring under the Forth for coal mining, and railway tunnels much longer than this have become relatively common in mainland Europe. The very recently opened Ceneri Base tunnel in Switzerland, which at 9.6 miles is virtually the same length, had a quoted cost of €3.6b.  There are several other sub-Alpine tunnels of recent construction.

“The Öresund or Øresund Bridge between Denmark and Sweden includes both a 5-mile (8km) bridge and the 2½ mile (4km) immersed-tube Drogden Tunnel over a similar distance and incorporates a dual-carriageway road as well as a double-track railway.

“The Lower Thames Crossing will provide two 2.6mile (4km) road tunnels under the Thames, with each being the third largest bored tunnels in the world, all part of a 14.3 mile new dual-carriageway road.  The budget cost for the whole scheme is £5.3b to £6.8b. The Crossrail tunnels in London are each 13 miles long and the London Tideway tunnel will be 25km long.

“As part of the under-Forth scheme, a double-ended underground station could be provided in Leith, with the south end at the Foot of Leith Walk and the north end near the Waterfront. An indicative first estimate of the cost of the under-Forth project is £4bn-£6bn, including the station at Leith, based on the out-turn costs of recent tunnelling projects.”

https://greens.scot/news/firth-of-forth-tunnel-at-heart-of-22bn-green-rail-revolution

image: Deltix Transport Consultancy (from Rail for All report commissioned by Greens)