I can't see the point in putting 195s on Airport-Liverpool at this stage, tbh. 156s are a perfectly good train so if a double 156 proves satisfactory on the route for the most part, what's the point in upsetting the apple cart? Yes, we know, sometimes trains would be short-formed, but if we're going to knock four-car trains down to three-car as a matter of course then they're effectively going to be short-formed all the time. Or, of course, we can increase four-car trains to six-car and then short-form the six-car trains (see post #2017).
Not to mention, if you introduce new stock on to two routes instead of one, it increases (I'm not saying doubles) the amount of immediate staff training required! I don't always follow the logic of how railways operate, sorry.
Why not introduce 3-car 195s on to routes that it has always been intended should get them (I, personally, can only guess as to which those are), and wait until some 2-car 195s are available before worrying about Liverpool-Airport semi-fasts? Then you could replace a four-car 156 set with a four-car 195 set, or, if you want a bit of extra capacity, replace a four-car 156 set with a 2-car 195/3-car 195 combination. To increase a four-car set to a six car set but to then immediately short-form it as a three-car set seems a bit counter-productive, to me.
