Overhead electrics might become a thing of the past as technology advances, especially given the huge cost of wiring routes.
Unless someone invents batteries with an impressive energy density and lower-losses than the OHLE system (which seems very unlikely to me) there will always be benefits to proper electrification.
I don't know your age, but electrification of the Chiltern Line WILL obviously happen if we're to get to Net Zero etc. it's not some quiet branch line, it's a London commuter line. And indeed a Birmingham commuter line.
Not just a commuter line - the middle part of it is also used by XC Voyagers on the Manchester-Bournemouth route (which I think should be a priority for electrification as it would allow XC to order dual-voltage EMUs making use of the 3rd rail and releasing Voyagers to strengthen other XC routes until further GWR (Bristol and Swansea) and LNER destinations are wired allowing some 800s/802s to cascade to XC).
Didcot to Oxford is not a quiet branch line either but that hasn't been electrified yet. If Chiltern procure a fleet of battery/hybrid units or similar then that will push electrification back even further into the realms of fantasy.
Ah of course, Net Zero, the mythical aspiration of the current Government, as long as it doesn't involve any unpopular policies which will cost them votes.
Electrification is normally seen as a vote-winner though (see the 'promise' to wire the North Wales Coast Line when Sunak announced the lastest HS2 cutbacks) - the current Government just prefers to direct capital investment funds at the road network rather than rail. The aspiration of the current Government seems to be to get everyone driving cars (eg. the plans to build yet more road capacity and proposals to water-down bus lanes in the disastrous 'plan for drivers') so they don't need to spend anything on public transport.
Didcot to Oxford would have been done if Network Rail had managed to deliver GWEP on time and on budget, but the HOOP system failed to live up to expectations allowing time for a change of Government (or at least transport minister, I forget exactly) to one that was less keen on rail and an excuse (the higher cost) to kick it into the long grass. If we had an electrification programme targeting net-zero then the 175s (which, if the 150s are anything to go by, have at least 15 years left to run) would be a very useful fleet for the interim period while the wires are being rolled out. You don't want to build brand-new DMUs as they would have a life well beyond the net-zero target date. The 175's life-expiry around 2040 would be perfect timing right as the electrification programme reaches peak performance (after ramping up from the UK industry having so little electrification to do for so long) so there should be some new EMUs coming in for newly wired routes allowing the 175s to be retired.
Just to return to the 175s ...
The route for which they would be ideal would be Manchester - Crewe - Shrewsbury - Cardiff - Swansea.
Not sure tbh. 3 cars isn't enough capacity on some services and they don't have corridor connectors. Ideally on a route that long you should have a shop or trolley service.
I'm fairly sure there was a trolley service when the 175s were used on the Marches Line. Agreed they could have done with having end-gangways and running in pairs on that route though.
My suggestion re using them on the Marches was tongue in cheek but they were ideal for that route given their level of comfort.
It's a service I used a lot pre-Covid (albeit only between Ludlow and Manchester) and honestly cannot remember ever having to stand*! Yes, people did stand but this was generally either because they suffer from the British reluctance to sit next to anyone to whom they have not been formally introduced or for short stretches* - yes, the 1730 from Manchester would be full & standing; after Stockport it would be 100%; after Wilmslow there would be empty seats.
And if they were concentrated on that route they could have provided ample capacity: 175/0 + 175/0; 175/1 + 175/0. The lack of through corridor connection is a drawback but not insuperable.
Argeed, apart from having to duplicate the trolley (or have one half of the train unable to access refreshments) the lack of corridor connections might not have been that big a problem for Manchester-Swansea. The bigger problem is that these services typically don't terminate at Swansea - they run on to Carmarthen and/or Milford Haven where 3 coaches is enough but splitting a non-gangwayed train in service is a recipie for leaving passengers stranded (this happened to my uncle the other week - a pair of 165s on his Portsmouth to Cardiff train split at Temple Meads, with just 2 coaches going through to Cardiff leaving him stuck in Bristol until the next Cardiff service). Really there should be three seperate services, a Manchester to Swansea (five coaches, hourly) a Swansea to Milford Haven / Fishguard Harbour (alternating each hour, with some being 2-car and others 3-car) and a Cardiff to Carmarthen (hourly, extending to Milford Haven every two hours and Fishguard Harbour twice a day for the ferry connections, 3-car and running non-stop (with the exception of Port Talbot Parkway) between Cardiff and Llanelli). 175s would be suitable for all three, particularly the express Cardiff to Carmarthen/Milford/Fishguard run.
Basically they were a mistake. An expensive incompatible micro-fleet with reliability issues.
But a glorious mistake as they were supremely comfortable.
The reliability issues seemed to disappear during Arriva Trains Wales' time as operator - I can't remember for sure but I think they were preforming better than most sprinter fleets in the 'Golden Spanners' reliablity tables. It all went to pot when TfW started making preperations to replace them. The mistakes in my view were the incompatible couplers and the lack of unit end gangways for such short units. Yes they are probably expensive to lease and run compared to 158s/159s, but I doubt any post-privatisation DMU can match those.
the 175s could replace 170s with Cross Country.
Only for the Cardiff services. The 175s aren't suitable for the other three routes where XC use 170s; the 175s might not be able to keep to time on Birmingham-Stansted due to differential linespeeds they cannot use and the other two are Birmingham local stoppers where the 170's suburban bodyshell is probably more-appropriate than the 175's regional express bodyshell.
