Anyone seriously believing that the Chiltern routes will be electrified is delusional. It won't happen, at least not in my lifetime.
Even newbuild DMMUs are significantly quieter and less polluting than the 30+ year-old units that they would replace and of course if even what is effectively a brand new line for EWR is being built without wires then why on earth would the Chilterns be electrified at huge cost and years of disruption?
There is a national target for Net Zero greenhouse gas (or is it just CO2?) emmissions by 2050. Not a 50% cut in emmissions or anything like that, but net-
ZERO. Yes, that is net and not absolute zero but it's not like we can just leave residual emmissions (however small - and I'll accept the emissions from a few 165s or 175s are unlikely to be significant enough to grab headlines) without addressing them. To reach net-zero, even the tiniest source of CO2 emissions will either need to be eliminated or an equal amount of CO2 will need to be removed from the atmosphere to offset the residual emissions (and there of course will be some).
Thus, if the Chiltern line is not electrified, somebody needs to identify how the additional emissions resulting from the decision are to be sequestered. North of Aynho Junction, the Chiltern line carries CrossCountry Voyagers, probably the most-significant source of diesel emissions on the UK passenger railway, and if I recall correctly was included in the aborted 'electric spine' proposal so presumablly carries a fair bit of freight.
If you ask me, Basingstoke-Reading and Didcot-Oxford-Aynho-Birmingham should be fairly high on the priority list for electrification, so that Manchester-Bournemouth can be worked by dual-voltage EMUs (OHLE + third rail), and it is the decisions to order large numbers of new DMMUs in recent years (195s, 196s and 197s) and to delete electrification from the scope of EWR that were delusional.
Bi-mode with batteries doesn't seem to have been a particularly successful option so far...
The only bi-mode with batteries (or 'tri-mode' as the responsible TOC call it) for the UK that I can think of are the class 756s for the Cardiff Metro and they weren't due in service yet anyway were they?
Please provide a link to any information confirming the plan 'in 15-20 years time' to electrify the Chiltern line.
No there is no source but we are in the speculative section of the forum. As a busy commuter line to London it's a major anomaly and I always wonder how much longer until electrification. Surely it will have to happen in your lifetime, unless you are old.
You won't get a link, but its certainly being looked at strategically within NR.
There were no timescales for delivery of individual sections (and thus it doesn't support the claim that the Chilterns would be wired 'in 15-20 years'), but I can give you a link to the interim report for Network Rail's decarbonisation strategy (TDNS)
https://www.networkrail.co.uk/wp-content/uploads/2020/09/Traction-Decarbonisation-Network-Strategy-Executive-Summary.pdf - this is an official Network Rail document and certainly recommends electrification of the Chiltern mainline, along with much of the rest of the network, by 2050 (just under 30 years time). Unfortunately, the Government has apparently refused to fund implementation of the decarbonisation strategy, but there were suggestions (I think in Modern Railways) that somebody (possibly the GBR transition team) is working on something similar but broken into smaller chunks that the Government might be more-willing to fund.
I believe the MD of Chiltern has recently literally stated that there is no current prospect of electrification hence the need for a hybrid fleet, or similar. That would suggest there is nothing on the horizon for at least a generation.
"No current prospect of electrification" could have very different meanings depending on your interpretation of the word "current". If they want to withdraw the class 165s at 40 years old then they need new trains ready around 2030. That's only 7 years away, and I would agree that there is no prospect of electrification allowing the 165s to be replaced by pure EMUs in that timeframe. The 175s, on the other hand, are ten years newer than the 165s and would be deployed on the Chiltern mainline (London-Birmingham services) which is more-likely to see electrification by 2040 (thanks to freight and XC usage north of Aynho) than the Aylesbury branch (where Wikipedia suggests 165s are more likely to be found).
Not necessarily, there's plenty of other places such a train could be used and so it being used for at least 10 years (as it'll take several years to electrify enough for to be usable by straight EMU's and longer still for the whole line to be done).
However even that assumes that such a train couldn't be retrofitted to allow electric pick up.
Converting a diesel-mechanical/hydraulic mutliple unit to allow electric pick-up sounds exceedingly difficult to me, and I can't recall reading of any examples of it ever having been done. You might be better off converting to an unpowered trailer unit (like a 4-TC) and building some powerful new EMUs to pull/push them around. Given the decarbonisation imperative, it is my view that procurement of any new units that do not allow for electric pick-up (or at least easy retrofittment of this) should be banned.
