I'd imagine it will resurrect much of the earlier L2E4 work including Newark Grade Separation, bundled in with PSU2, Digital Signalling and the NPR work for York - Newcastle. An approach and electrification from Hambleton Junction westwards to Leeds will be faster than accessing via Wakefield Westgate too. In terms of what is needed for 140mph as someone asked earlier - lots, all yours for say £3-5bn:
- OLE upgrading including fitting Carrier Wire Neutral Sections, HS2P conversion, modification/improvement of clearances and lots of Traction Power supply reinforcement. The equipment on the east coast has been receiving some funding in the past to upgrade to Mk3D and improve it's resilience in known trouble spots. Probably some lifting or rebuilding of certain overbridges to gain the necessary clearances.
- Closure of open platform faces in potential 140mph sections (Biggleswade, Sandy, Stevenage and Northallerton)
- High security palisade fencing throughout
- Aerodynamic modifications in tunnels
- Closure of any Level Crossings in >125mph sections. Some are already in play or anticipated (Lindsells, Love Lane (for Wintringham), Copmanthorpe No.2, Thirsk Station if it gets AFA funding to develop beyond design/feasibility).
- In cab signalling
- Civils works (underbridges, any weak earthworks etc.)
- Track replacement for any pre 1978 CWR and any non pandrol fittings. Lots of track fettling to improve ride quality.
- Swing nose points on the Fast Lines
- Train to structure gauging.
- Probably extra access points as you won't be red zone working on 140mph lines.
Sections to upgrade to 140mph?
1. Woolmer Green to Connington with a slight reduction through Offord
2. New England to Stoke Tunnel
3. Sections north of Grantham to just south of Bawtry where curvature allows.
4. Doncaster all the way through the Selby Diversion up to Colton/Copmanthorpe Area
5. Skelton Junction to around Croft on Tees
6. Perhaps north of Newcastle from say Littlehoughton to Spittal
Other schemes will help in terms of capacity:
- You'd also want to resurrect HW4T; it will also in any event be needed at least as far north as the proposed site of the Alconbury Weald station.
- Grade separation at Doncaster to/from Leeds
- Remodelling York North Throat/Skelton Junction
- Any freight loops between York and Newcastle
- Grade separation at Northallerton
- Darlington Station remodelling (funded)
Forget Closing Welwyn North and adding extra Viaducts and tunnels in the area; I suspect these will be managed by cab-signalling and timetabling modelling.