I read this forum from an environmental / ecological / planning interest rather than a conventional railway enthusiast viewpoint. I'm aware of the debate over whether to give future intercity trains all-electric power or additional diesels to enable them to move off-grid to places the authorities don't want to electrify I'm aware that lugging diesel engines around when running electrically is a waste of power... but equally that running diesels under the wires is environmentally and economically bad news and that this logic informs the choice of dual-power trains, while most rail professionals would rather see the railway electrification system spread more widely and lighter all-electric trains underneath it. I also understand that having dual-mode trains will reduce the temptation to electrify further So, here's my thought. Diesel trains presumably use enormous amounts of energy & fuel for acceleration to line speed then throttle back to cruise at a much lower kilowattage when running at a steady speed. Set the trains up so they can switch between electric and diesel power in motion, or vice-versa. Then string up 2 to 3 miles of overhead power heading away from every station they stop at, and up any major inclines on their routes The electricity - vs - diesel fuel savings from this negligible amount of electrification would be proportionately greater than electrifying the whole line through, the performance benefits of having electric power for acceleration compared to onboard diesel would mean better timings, and less diesel wear'n'tear and pollution AND - if proven to save money soon every major station off the electrified network that served stopping dual-mode trains would have a few miles of catenary. At which point it becomes viable for local operators to campaign to link the sections, or to wire up local branch lines. Some places would no doubt remain as islands cut off from the main network but if those islands grew the use of diesel fuel to power trains could be progressively reduced, until its economically straightforward to bridge the links and remove the diesel pods from the trains or remove their number (Ie, a train that always reaches 125mph electrically doesnt need 4500 diesel horsepower,it can carry fewer diesels and maintain the same acceleration profile) .. and after a while it'd be freight operators calling for infill electrification projects too What do you think?