It's actually about providing more indirect services.
It's your opinion that 2tph from Liverpool is sufficient however as this route has double the passenger flows into Manchester than out the other side I would say you're wrong. The simple fact there is that useful trains from the east are not carrying on west with lots of passengers but heading down to Manchester airport with just a few.As new tracks have been built out of Liverpool specifically to provide more capacity, it would seem a bit strange not to make use of them (retaining, or increasing, services to Newton Le Willows).
Yes it is my opinion, so we'll agree to differ on that point. We should remember that the trains going east of Manchester are not just serving Leeds. They are serving the busy Huddersfield to Leeds corridor and multiple destinations beyond Leeds. Therefore, even if they left Manchester empty (which they're not) they would still be serving passengers further down the line. Fast trains going west over the Chat Moss are only serving Liverpool, not a multitude of destinations beyond.
It's certainly my opinion that numerous other services shouldn't be axed in order to make way for more than two fast trains per hour on the Chat Moss. As 158756 pointed out, that doesn't include other fast(ish) trains between Manchester and Liverpool via Warrington. I think it's worth pointing out that at the moment there is one TransPennine Express service between Manchester and Liverpool over the Chat Moss. I believe the plan is to have two TransPennine Express trains per hour in future so they will be making use of the improved infrastructure and this will do much to meet demand. To go straight from 1tph to 4tph seems excessive. To do so at the expense of a link to Piccadilly and Manchester Airport seems a retrograde step.
Your argument seems centred around you in Durham would lose direct services to the airport, but this is exactly one of the problems being talked about where every small town and city from afar sees simply being on a direct destination board as somehow vital. It's not. No one is asking you to make a choice between Manchester and Liverpool, because the trains would obviously serve both. More throughput = more connectivity = more opportunity to get to/from the airport for more people not less.
Put it this way, you might value your direct service to Manchester airport from your small city of 90,000 or so people. But you've got a comment up there from someone who lives in a major city conurbation on the opposite side who is basically stranded at the airport if he arrives into manchester airport on a sunday evening.
Actually my argument wasn't centred on that at all. It couldn't have been because, as others have pointed out, Durham has already lost that service. I was simply pointing out that I used to find that service useful, both for the airport, south Manchester and connections from Piccadilly, to challenge your assertion that there wasn't much demand for it. I also have no complaints that the service has gone. I personally found it more useful but I recognise that many others will find the direct service to Liverpool more useful.
You claim that we don't have to make a choice between Manchester and Liverpool because trains would serve both, which is true. However, you would have to make a choice between Man Piccadilly/Airport or Man Victoria/Liverpool. The current plans which allow both to be served seem the best solution to me.
I'm not dictating specific service patterns here, only suggesting levels and types of connectivity, but I am saying that starting from a perspective of "who should have direct trains to manchester airport" is completely the wrong way to determine service patterns and results in inefficiency and poor levels of connectivity all round. "Local or logistically sensible" should be the rule, with urban connectivity around hubs being prioritised.
You may not have been dictating service patterns, but you were certainly suggesting some, specifically 2tph Leeds - North Wales, 4tph Leeds - Liverpool. I was respectfully disagreeing with that suggestion for reasons I have made clear. I am still puzzled as to how you see axing all fast, direct links from West and North Yorkshire to Piccadilly and the Airport in order to quadruple the current service provision over the Chat Moss to Liverpool as improving efficiency and connectivity. You say urban connectivity around hubs should be prioritised. I agree. Which is why it's vital that Piccadilly retains a service. As I have already said, if you're approaching Piccadilly from the west, which some of these services will be, it would be odd not to continue the short distance to the airport and terminate there.
I think I should also point out that if you had 4tph Liverpool - Leeds you would use paths out of Lime Street that could be used to serve other destinations. Perhaps Scotland at some point in future. Everybody would therefore lose out.
Capacity is being increased on the Chat Moss route from a position where it had no TPE services. I very much doubt that a mile of four-tracking allows a jump from 0 to 4 fast trains per hour, and a stopper certainly couldn't do Huyton-Manchester without getting in the way of said fast trains.
Liverpool also has 2 fast tph via Warrington to Manchester. Why does Liverpool need an increase to 6tph to Manchester from an already frequent 4tph, at the expense of local services and connections from Yorkshire and the North East to Manchester's main station? Would the people of Yorkshire find Manchester Piccadilly and Airport or Llandudno and Holyhead more useful destinations?
Durham has no daytime service to Manchester Airport at present anyway. Running all TPE trains to Liverpool/Wales would mean no direct services from the east(or Wales) to Piccadilly, and consequently having to change twice to reach any destination south of Manchester, using infrequent stopping services for part of the journey.
Precisely. It would be ludicrous to sever all services to Piccadilly. If you're going to serve Piccadilly, you might as well go on to the airport. In future, services won't be able to cross the throat of Piccadilly from Guide Bridge to the through platforms so trains from West and North Yorkshire to Picc would be unable to continue to Liverpool/North Wales anyway.