All rather odd. Reusing the name 'Castles' is either a nice hark back to the past, or sacrilege I guess, depending on who you ask. I just hope that long-term they don't stick with the idea of giving each named unit a different name for each driving vehicle, as for a multiple unit that really doesn't make much sense to me.
Using class 255, I know exactly why they picked it, but it's a bit pointless. Seems like undoing the change made early in the HST's life to renumber the power cars as locomotives (which in my opinion they kind of are really!) is change for the sake of change, to unnecessarily distinguish them from the bigger HSTs which before long will cease to exist.
Possibly the biggest gains from that really, apart from the frequency improvements, are those going from 153s to 158s and the 2+4s. That's quite the upgrade really. Far more is changing there for the benefit of the passenger than from HST to 800 I would say, without having been on one yet.
Since this is a general thread, any news on how they're getting on with the units earmarked for VTEC or TPE?