In the UK the Great Western Region, GWR, line from London to Cardiff is being upgraded from diesel to electric. I travel from Oxford to Cardiff every few weeks and have been keeping an eye on what's going on from a civil and electrical engineering point of view. It all looked a bit quiet in 2015, not many piles going in, not that I could see, great piles of piles going rusty for months, a few bridges being raised to allow for the overhead lines, substations poping up (that might have been 2014 also).
This year, 2016, steel galvanized gantries are spreading from Didcot railway station, they're moving faster towards Reading as far as I can see down the track. I'm looking at this stuff being built and thinking shit man that's a lot of steel and concrete, to be fair it's not much concrete when you compare it to a motorway for example. It's nice watching the infrastructure go in bit by bit, it's a big project.
Trains are or will be Hitachi hybrid diesel/electric so they probably run them on diesel through the Severn tunnel and a bit more. In Green terms it's a lot of steel.
And GWR now changed their livery to dark or flat olive green, nice colour I like it.