Philip
On Moderation
I'm not sure how many DMUs can be configured to run on only 1 engine dynamically. I believe the 185s can utilise all the engines when they need to, I'd guess most DMUs either have the engine off or on for the duration of the trip. Not that it would make much difference in terms of cost - the amount of diesel you'd save would be negligible. Staff costs are the highest operating cost. If you need to cut costs they will, inevitably, have to be reduced. It's possible to reduce the bill through means other than compulsory redundancies such as not replacing natural turnover and salary cuts but the diesel bill barely even registers against the staff bill. Not to mention some TOCs (& NR) don't have a substantial diesel fleet (GTR & SE in particular)
I guess on the point of salary cuts, rest day working will be an obvious thing to cut back on, at least away from train crew and dispatcher roles. Sunday as part of the working week is another area they might look at.