Re: replacing/reboring low bridges and tunnels
Tunnels and bridges are expensive, but this is a very long twitter thread on why electrifying them beats coasting: https://twitter.com/25kV/status/1187817155385090048
Basically: making coasting work safely and reliably is a pain in the arse which lands up costing as much as electrifying the section.
Using batteries for discontinuous electrification is also under active consideration and a test train which does exactly that ran for a while. One example is: https://www.railway-technology.com/projects/independently-powered-electric-multiple-unit-ipemu-essex/
Hydrogen is rather covered by the original article, but the applications for which it's being considered are much more "discontinuous electrification" and not really actually looking to replace OLE at all, despite the wording of the article. OLE is always better, but historically in this country we a)built lines before it was an idea then b) didn't spend the money adding it, so now adding it will be very expensive and disruptive. It's a good idea though.
Biting the hand that feeds IT
