- Powered heavier-than-air flight with large cargos and ranges will require energy storage densities on the order of present-day fossil fuels. That might be provided through continued consumption of fossil fuels (with offsets), by synthetic analogues (electricity-to-fuel, by several different routes), or at a remote stretch from biomass-derived fuels (the availabilty-vs-demand situation makes this highly unlikely).
- Rail is exceptionally well-suited to electrification. Generate electricity elsewhere, feed it to the rail system. This works quite well for continental trave. Oceangoing trains have achieved limited success.
That said, there are a number of reasonably traversable boundaries. The Channel Tunnel ("Chunnel") between UK and France, and Öresund between Denmark and Sweden, are two examples. Bridging or tunneling Gibralter and the Bering Strait have long been proposed, other links might be made between Malaysia and Sumatra across the Malacca Strait, along the Sunda Islands, and finally across the Timor Sea to Australia. The Timor sea is relatively shallow, at about 200m (~660 ft), though that's far deeper than the English Channel's 63m average (~200 ft).
The hard crossings would be the Atlantic. There'd likely be call for two of these, one from the British Isles to a landfall in Newfoundland, another from Recife, Brazil, to Monrovia, Liberia, or Freetown, Sierra Leone.
One possible option would be to construct submerged floating tunnels. Norway is considering these as options for crossing its fjords, which are too wide for traditional bridges and too deep for conventional tunnels. A floating tunnel, at a depth of about 20--50m (perhaps somewhat deeper in open ocean) could provide a potential transportation route across long stretches of open ocean. Speeds could conceivably range from lower-end high-speed rail rates to near- or beyond-supersonic speeds (with an evacuated tunnel), though I'd suspect that 200--300 kph (~120 -- 180 mph) would be more viable. For the Newfoundland-Ireland link, about 3,000 km, this equates to a 10 hour crossing. Longer than by present-day aircraft, but far faster than ship, or even airship (typically at 100-200 kph).
Safety, cost, engineering, sabotage, accidents, and all manner of other issues would of course be concerns. Piloting such a project as an automated cargo channel might be one option for development. Staged links might also be developed, say, within island chains (the Faeros already have an underwater tunnel network), say from Great Britain to Ireland, and from Scotland to the Orkneys, Faeros, and Iceland, or from Newfoundland to Prince Edward Island and Greenland.
But in a world of impossibilities, this is, if not especially straightforward, at least within the realm of the possible.
There are a few facts which are obvious:
- Powered heavier-than-air flight with large cargos and ranges will require energy storage densities on the order of present-day fossil fuels. That might be provided through continued consumption of fossil fuels (with offsets), by synthetic analogues (electricity-to-fuel, by several different routes), or at a remote stretch from biomass-derived fuels (the availabilty-vs-demand situation makes this highly unlikely).
- Rail is exceptionally well-suited to electrification. Generate electricity elsewhere, feed it to the rail system. This works quite well for continental trave. Oceangoing trains have achieved limited success.
That said, there are a number of reasonably traversable boundaries. The Channel Tunnel ("Chunnel") between UK and France, and Öresund between Denmark and Sweden, are two examples. Bridging or tunneling Gibralter and the Bering Strait have long been proposed, other links might be made between Malaysia and Sumatra across the Malacca Strait, along the Sunda Islands, and finally across the Timor Sea to Australia. The Timor sea is relatively shallow, at about 200m (~660 ft), though that's far deeper than the English Channel's 63m average (~200 ft).
The hard crossings would be the Atlantic. There'd likely be call for two of these, one from the British Isles to a landfall in Newfoundland, another from Recife, Brazil, to Monrovia, Liberia, or Freetown, Sierra Leone.
One possible option would be to construct submerged floating tunnels. Norway is considering these as options for crossing its fjords, which are too wide for traditional bridges and too deep for conventional tunnels. A floating tunnel, at a depth of about 20--50m (perhaps somewhat deeper in open ocean) could provide a potential transportation route across long stretches of open ocean. Speeds could conceivably range from lower-end high-speed rail rates to near- or beyond-supersonic speeds (with an evacuated tunnel), though I'd suspect that 200--300 kph (~120 -- 180 mph) would be more viable. For the Newfoundland-Ireland link, about 3,000 km, this equates to a 10 hour crossing. Longer than by present-day aircraft, but far faster than ship, or even airship (typically at 100-200 kph).
Safety, cost, engineering, sabotage, accidents, and all manner of other issues would of course be concerns. Piloting such a project as an automated cargo channel might be one option for development. Staged links might also be developed, say, within island chains (the Faeros already have an underwater tunnel network), say from Great Britain to Ireland, and from Scotland to the Orkneys, Faeros, and Iceland, or from Newfoundland to Prince Edward Island and Greenland.
But in a world of impossibilities, this is, if not especially straightforward, at least within the realm of the possible.