I think even if Bedford Cambridge doesn't get built, Oxford to MK as OLE still makes sense once Didcot to Oxford is done. However it would either need Basingstoke to Reading or Battery units for Bedford (or both) to make the best use of it.
I think hourly is still borderline. Half hourly certainly, but if you had a relatively short spur, I might look at batteries first. So I'd say Aylesbury should be battery operated even if the whole Oxford to Bedford route is wired.
I wouldn't unless it was part of a serious intent to wire the Chiltern.
Indeed. Although with a 4 car desiro type unit even 20 miles at 60mph should be viable with a relatively cheap set of cells.
Don't forget the IETs.
Electrification of Chiltern would be advantageous, but it doesn't really change the calculations for doing EWR
Agree, and even afterwards it may not make sense to wire the Marston Vale if a decent battery unit can be supplied. Oxford-Bedford could charge from Bletchley to Oxford and Back, and Bletchley-Bedford services could charge in the platforms during the turnround at either end. There's so little through traffic on the route not wiring it wouldn't be a problem. It'd be better if it was wired properly, but I could understand if it wasn't.
If the Chiltern main line was electrified, then you'd want to do Bicester Village to Oxford as well, which is a chunk of EWR. And I'm sure there would be scope for shared electrical infrastructure at Bicester etc
Yes but electrification of the Chiltern line is only beneficial if it gets all the way into London (or you have battery-EMUs). We're going to be waiting for an awful long time before any serious design work is done on Chiltern. EWR is likely to be targeted Politically as a 'quick win' at some point in the next 5-10 years.
DMUs chugging through London - even with hydroflex they'll still be operating within the London boundaries in DMU mode - would surely be politically be more awkward than a route running through Bucks and Oxfordshire
It's about what can be achieved (or at least started) before the next election. Many bigger political wins are discarded for fear of handing the other side an open goal. And the political goal is to electrify lines, not eliminate DMUs, which is subtly different.
Yep I was assuming that Didcot/Oxford to Bletchley would be wired sooner than Marylebone to Bicester/Oxford. But of course, the latter would probably bump up the list if it fed into an already-wired Bicester Town. Chiltern doesn't really hit any wires, whereas EWR flows into both Bletchley/WCML and Bedford.