Guildford has many challenges, including a possible virtual doubling, if all the current ideas come to fruition, of train movements (including 6 TPH Portsmouth, 4TPH North Downs, 2TPH to Heathrow, increased New Line Services , Woking Stoppers,etc.).
Platform 0 is almost within the footprint of the proposed Solum redevelopment (under planning appeal at present) of the east town side entrance to the station. The Solum plan is like others from this developer basically a development of commercial/housing units with limited benefits to the railway e.g. a very small booking hall is proposed for Guildford. No clear plans have been published by Solum to show how platform 0 can be accommodated.
The map posted by Marky T misses one point - there is a lot of discussion about Heathrow services (part of Runway 3 approval) which will require terminating platforms at the station, and consideration of passenger circulation as it will be a major traffic generator. I would propose terminating platforms need to be between the main north/south running lines to make for operationally robust services, this would mean northbound services using platforms more to the west side of the station layout. The ability of northbound services to access, as they leave the tunnels, platforms to the west of the layout is constrained by car park and access road to car park, at present curvature is approaching the maximum desirable.
Guildford Station with its network of connections including both Heathrow and Gatwick needs to be viewed as a transport hub with proper integration of transport modes including buses. Network rail have land holdings to the east and west of the station that if properly considered in totality would allow this interchange to be created, as well as replacing ageing road infrastructure that crosses the railway.
Network Rail need to have a strategic look, now, at what the station will look like in 15-20 years time and ensure railway land is preserved for use by the operational railway, identify how curvature issues from the south can be mitigated, and look at creating a proper transport hub. Network Rail are in danger of being distracted by the short term gains from a series of property developments, rather than ensuring Guildford Station is made fit for the 21st century.
Finally, Guildford might be a candidate for a flyover to bring the Reading line across the Woking line at the north of the station -- with only minor land take this is achievable. This would reduce conflicts between the main line and increased services on the North Downs corridor and opens up the provision of cross Guildford services on the east west axis (this would link the proposed Guildford West and East Stations currently being discussed).
