No new rolling stock is proposed
Well it depends what you mean by 'new'. If you mean 'additional' (as opposed to brand new and smelling of paint!) then that's not correct. This is an excerpt from the rail proposals for the Stockport area:
'The service between Manchester Piccadilly and Marple, via Bredbury, would run every quarter of an hour under the TIF proposals. There would be extra seats on peak-time rail services to reduce overcrowding with station improvements at Bramhall, Woodsmoor, Reddish North, Brinnington, Bredbury and Rosehill.'
Increasing frequency alone, from the present three trains per hour to four trains per hour, will require additional rolling stock, and will increase capacity by 33%. On top of that, we are promised extra seats - i.e. more carriages - on peak time services.
So there will be more rolling stock and significantly increased capacity. But what bothers me is where will these additional passengers park? Parking anywhere near Marple station on a weekday is already very difficult, and I'm not aware of any plan to expand the car parks.