First of all I am looking at this from the viewpoint of a traveller into the NW from Yorkshire. A quick look back: I started using Transpennine services in around 1980, 1 tph via Huddersfield, more stops than today, 6 or 7 carriages, loco hauled, Leeds Manchester took around an hour from memory. You ended up in Man Vic which as a majority of onward connections left from Man Pic was useless. You did have an option to change at Staylbridge. A major change to the service occured in the mid 80's, 3 car 158's, 3 or 4 per hour via Guide Bridge into Piccadilly, Leeds - Manchester in about 55mins. Arrival into Pic was a game changer, saving a good 30 mins on journeys involving an onward connection. Liverpool trains via CLC lines, serving places like Warrington, Liv Sth Parkway. Airport services came on line in this period as well. The service was OK, I used it once or twice a week for 20 years, the odd disruption, but on the whole acceptable. This pattern persisted until 2014 ish when they tried to shoehorn extra transpennine services in. That was mistake 1, instead of running more trains run longer trains. Then fast forward to 2018 and the re-routing of services back to Victoria, a backwards step from the point of view of Yorkshire travellers. No through ticketing on Metrolink. Too many trains leading to a hopelessly unreliable service, existing connections broken, e.g. York - Warrington goes from through train to a change and because everyone wants Oxford Road or Piccadilly airport trains from York are even more rammed than pre 2018. For a lot of journeys involving a change in Manchester we are back to 1980 journey times or worse end to end, and with less reliability.
My solution would be quite simple for Transpennine North, run everything except one train per hour into Piccadilly low numbered platorms via Guide Bridge and terminate them there. Run Pic - Airport as a an almost self contained route, ideally with dedicated platforms, with a mix of stoppers and fast trains, dedicated stock with plenty of luggage space. Send one TPE train per hour via Victoria to Liverpool to maintain Liverpool connection. This would remove 2 tph from Castlefield, and becuase you terminate in Piccadilly onward journeys are easier, with good signage walking route to 'Airport shuttle' at Piccadilly would be easy. Transpennine South would also terminate at Piccadilly. Manchester - Scotland services would still need to terminate at the airport or somewhere else owing to a lack of terminating platforms for this route at Manchester. If you want to use the Ordsal chord use it for short distance local services. The 1 tph North Wales service used to manage to terminate at Pic, I dont know how much operating difficulty it caused. Sheffield - Liverpool remains 1 tph but with longest trains major stops can accomodate, remove minor stops on this service, so that towards Liverpool it only stops at Warrington, Widnes maybe, and Liv Sth Parkway
Longer term is there space for a Platform 0 at Manchester, and maybe even a '-1', how easy would this be?
