I’ve had the idea floating around in my head for years, and other people have had similar ideas too.
Prime Minister Boris Johnson has been proposing a bridge to do the job, but I feel a tunnel would be a much better option as it would avoid issues with high-sided vehicles getting blown over when the weather gets a bit frisky, as well as avoiding vision problems caused by fog.
— ConservativeChitChat (@ConservativeCCh) December 20, 2019
My first option is for a simple 21-mile tunnel from near Port Patrick in Scotland (to the west of Stranraer) that spits people out into Northern Ireland somewhere between Groomsport and Donaghadee near Bangor.
My 3rd Option is more ambitious, and calls for 2 tunnels. The first tunnel runs from near Whitehaven in Cumbria to the Isle of Man, and the second tunnel runs from the Isle of Man across to Ireland.
One snag I’m aware of is that of a rail based tunnel, and the difference of gauge of track used.
In mainland Britain we of course use “Standard Gauge” (4ft 8.5″), while over in Ireland (including the North) they use a wider 5ft 3″ (1600mm) width standard.
This would likely require the building of an interchange terminal at the Irish end.