Considering the article is talking about the UK, which recently axed a significant portion of its new high-speed railway corridor: don't count on it.

Even worse: railway electrification is not at all a given in the UK. A big downside of being the first country to roll out railways is that a huge number of railway lines (crucially, including tunnels and overpasses) were built to the dimensions of early trains. In practice this means that electrification isn't just adding some wires, it means having to re-dig all of the tunnels and having to raise all of the overpasses. To illustrate, the UKs universal loading gauge is small enough that you can't even fit regular intermodal container trains into it - and that's without overhead wiring!