I wonder about this - the 701 fleet offers no real capacity uplift in the metro fleet at all as it is today, but the capacity benefit was of course the 707s when they were introduced (and indeed the 701s that replace them) not replacing anything. That being said, they did allow 450s to be cascaded to longer-distance routes, so some of that gain would have been lost for capacity benefits to the faster services. I assume the 450s the 442s will displace aren't coming back onto metro routes in which case in a few years' time there could well be another capacity shortfall. If there's room to retain the 707s it could be useful but I somewhat doubt there is, and it also breaks a franchise pledge about toilets.