it would be better if a spare 150 could be sourced to run the llandudno shuttles maybe a 175 could be freed up for extra capacity in south wales then. i.e. a 150 in South Wales could effectively swap with a 175.
As has been said before, the Llandudno shuttles are simply filling-in time before returning to Manchester, and also, incidentally, providing connections to/from the Holyhead-Birmingham/Cardiff services at the Junction. All neatly-planned really, and a credit to Arriva Trains Wales.
So if the shuttle part were to be replaced with a 150, it would mean the Manchesters have a lay-over at the junction of 1 hour, which is not very efficient use of stock, especially as they also have a long layover at the other end in Mayfield loop in Manchester. Also, through passengers to/from Llandudno would have a hitherto unecessary change at the Junction.
If the "shuttle" were to run through to Manchester as a 150, it would result in gross-overcrowding, especially on the Chester-Manchester section.
I appreciate running an almost-empty 2 or 3 car 175 from Llandudno to the Junction and back seems wasteful, especially in view of overcrowding on other lines, but it is difficult to see what could be done without recasting the whole Llandudno-Manchester timetable, which would mean negotiating new paths through the already busy Ordsall Lane-Piccadilly section, and a knock-on effect on TPE and Northern services.
EDIT - apologies to
PHILIPE and
tom1649, who I now see have made the same point while I was composing this detailed response.
--- old post above --- --- new post below ---
As has already been mentioned, the shuttles are interworked with the Manchester services. They aren't using a 175 for the sake of it.
One option would be to remove all the through services to Llandudno and run a half hourly shuttle using a 150. I have the impression that ATW see the Llandudno branch as an operational inconvenience anyway and that they'd rather run everything to Bangor instead.
I get that impression too sometimes. For example, next Sunday the 7th September, is the last day this year for Sunday services on the branch - hardly the middle of winter yet!