You mean like the single class 153 that I saw creeping off to Spalding last week?
I agree it won't get done, but because this is the UK. As has been said on another thread recently, investment will be too little, too late and penny-pinching so that the full benefit isn't gained.
Network rail and the many layers of sub- and sub-sub-contractors may be partly to blame, but there is no sign of government commitment to a clean and effective railway.
Also the fact that Stamford is served by a hourly XC service which takes around 10 minutes to get to/from Peterborough and it's no surprise why Peterborough is seen as the railhead for Stamford even though the latter has it's own station.
Apart from the daily Peterborough to Doncaster via Lincoln, daily return Nottingham to Spalding via Peterborough or the Newark Northgate to Peterborough via Lincoln which is a new one to me, all services between Peterborough and Lincoln are more or less on the hour and all call at all stations to Lincoln which is why the powers to be never mind the signal box opening hours don't see why they ought to improve the service.
Yes it would be nice to extend the Kings Cross - Peterborough Class 365 services to Stamford and Spalding but I would much rather prefer they 1. Extended all Peterborough to Lincoln services to Doncaster calling all stations on a hourly basis, 2. Ensure departures from either end leave at a set time which is the same time past the hour on the hour, 3. Maybe look at expanding the services to have 2 car trains.
As to Stamford, simply extending the Leicester XC services to March would allow it to improve the service that Whittlesea gets for one by introducing a hourly service as it is a commuter town on the outskirts of Peterborough much like Spalding and Stamford are and by reinstating one of the bays at March you have a already made platform to terminate/start these services plus stations from Leicester to March will see 2tph pretty much all day.
But I fear we are moving away from the theme which is Werrington Grade Separation, the only remaining Grade Separation that reminds in the Peterborough area and it's something I don't think can be done easily and that's access from the south end of the yards to the March lines at Peterborough as at the moment they have to cross all running lines to get a freight from the yard to March.
That's something that I think is more important then trying to do the same for passenger services coming from London as freight services are a lot slower and longer so anything that can ensure they move quicker without impacting on passenger services is a good thing.
I look forward to seeing the completion of the Werrington Grade Separation and I look forward to the frequent/regular updates here.