In partnership with a infrastructure company with the DfT being kept away from the partnership, I would do the following:
1. Remodel Leicester itself and the surrounding approaches so reducing conflicts and making it OHL ready.
2. Electrify Market Harborough and Corby to Leicester first with Leicester being the changeover point from Diesel to OHL and vice versa.
3. Once Point 2 is completed, then work north of Leicester to Nottingham and Sheffield via Derby and Langley Mill.
4. Enough Class 800s to replace all HSTs and Class 222s with a equal mix of 5 and 9 coach sets with the HSTs being retired by no later then Dec 2020.
5. Service wise, might be wise off peak to run a 10 car between London and Leicester with 5 going to Nottingham and 5 going to Sheffield.
Personally I would like to see 2 new platforms built on the East side of Leicester along with grade separation of Wigston and Knighton junctions (for a restored service to Burton on Trent) so the cross country services do not need to cross the fast lines. Electrification extended from Market Harbrough to Leicester.
Platform 1 would be for Northbound IC services to Nottingham/Derby/Sheffield
Platform 2 would be for Southbound IC services to St Pancras and would be non-stop after Leicester
Platforms 3 & 4 would become platforms where new electric 360 services would terminate
New platforms 5 & 6 would be for Ivanhoe services to Nottingham, restored services along Burton line and Cross Country services to Birmingham and East Anglia.
The IC Service patten from St Pancras would be
2TPH to Sheffield
1 fast calling at Leicester - Derby - Chesterfield- Sheffield
1 semi fast calling at Leicester - Loughbrough - East Midlands Parkway - Derby - Chesterfield- Sheffield
2TPH to Nottingham
1 Fast calling at Leicester - Nottingham only
1 Semi fast calling at Leicester - Loughbrough - East Midland Parkway - Nottigham
Alternatively if stopping at both Loughborough East Midlands Parkway lead to an unbalanced timetable then either the Loughborough or East Midland PW stop could be added to the fasts.
With extra EMU's the electric service from St Pancras would 2 TPH to Corby calling at
Luton/Luton Airport Parkway alternate - Bedford - Wellingborough - Kettering - Corby
2TPH to Leicester
Luton/Luton Airport Parkway alternate - Bedford - Wellingborough - Kettering - Market Harbrough - Leicester
Would this require somewhere for IC services to overtake the fast? If so then with Beford due s rebuild then platform 5 could be added so current platform 4 become a through platform for non stop services?
Finally with the grade separation of Wigston and Knighton Junctions and 2 new platforms at Leicester then I wouuld like to see the East Midlands Franchise take on the Cross Country services along with their 170's. The Birmingham to Stansted could be interworked with the Nottingham to Norwich st that you would have
1 tph Birmingham NS - Nuneaton - Leicester - Melton - Oakham - Stamford - Peterbrough - Ely then alternate Cambridge - Stansted or Thetford - Norwich
1 tph Nottingham - Grantham - Peterborough- Ely then alternate Cambridge - Stansted or Thetford - Norwich.
Finally Ivanhoe services between Leicester and Nottingham would be extended to Birmingham calling at all stations and a Derby to Leicester via Burton service calling at Peartree - Wellington - Burton then reopened stations along the Burton Leicester line.
XC would take on the displaced 222's for Nottingham- Cardiff services
Just a few thoughts