Been thinking about the SWML and Windsor Line metro routes lately, and it has got me wondering how you could achieve a standardised 4tph service on each of the branches. Assuming 20tph on the SWML slows out of Waterloo is feasible, I would be looking at 8tph going towards Kingston, 8tph going towards Motspur Park and 4tph going towards Surbiton, with an additional 4tph to Surbiton starting on the fast lines then switching to the slows. I would envisage that such a service pattern is feasible:
SWML slow lines (all services call at all stations en route)
00/30 Chessington South
03/33 Shepperton
06/36 Guildford via Cobham
09/39 Guildford via Epsom
12/42 Waterloo via Kingston
15/45 Chessington South
18/48 Shepperton
21/51 Hampton Court
24/54 Dorking
27/57 Waterloo via Kingston
While this does provide 4tph for each route, combined sections where 8tph run are not at even intervals. This could be fixed once Crossrail 2 comes on line since you can transfer some of the branches onto it.
SWML fast to Surbiton, then all stations beyond
12/42 Basingstoke
27/57 Alton
Under this proposal, there would no longer be a Waterloo - Woking stopper on the SWML, since all trains would continue beyond. The bay platform at Woking would be reused for my proposed duplication of the Chertsey service via Hounslow, as listed below.
Windsor Lines
03/33 Windsor & Eton Riverside
06/36 Waterloo via Kingston
12/42 Woking via Hounslow
18/48 Reading
21/51 Waterloo via Kingston
27/57 Weybridge via Hounslow
Kingston and Hounslow trains call at all stations en route.
Windsor and Reading trains run limited stop to Staines, calling at Vauxhall, Clapham Junction, Richmond, Twickenham, Whitton and Feltham.
Since the line is only two track with frequent level crossings, there is less scope for adding additional Waterloo trains here. The Hounslow rounder is withdrawn, but I would extend the proposed West London Orbital service from Hounslow to Twickenham to replace the missing link.