The current detour via Watford High Street slows the DC lines considerably. The WCML needs to be a viable 6 track railway. The Met line can take over High Street enabling the 6 lines to run alongside the FL/SL.
You are in danger of answering your own questions.
How does Bakerloo service Kilburn to Wembley without using the WCML?
In a tunnel.
Watford LUL to London is nothing like an hour on the Met and High Street to Euston is nothing like 20mins on the DC lines.
The proposal is to remove the detour via High Street and run the DC lines along the WCML.
High Street would divert to the Met Line and Watford LUL would close.
Currently High Street is 50mins to Euston and Watford LUL is 42mins to Baker Street.
Can I summarise your proposal to improve capacity on the WCML south of Watford? It appears to be:
Extend the Bakerloo Line, in Tunnel, for around 8km and 6 Underground stations. Let’s say £3-£4bn.
Straighten out the loop of the D.C. line around Watford (which will save, at best, 30 seconds), that will be around £400m (it includes 2 large viaducts, about £20m of commercial property, and is adjacent to the busiest long distance main line in the country)
Extend the Met to Watford Jn (£400m). Remember that’s this scheme is about improving connections to/from Watford, not improving connections to/from central London.
So £4-5bn of infrastructure. Which would take around 12-15 years to deliver from a standing start.
Implications:
Watford High St would only be accessible from the Met line. This station has nearly as many inbound passengers from the D.C. line stations south thereof than passengers for London. They are going to the jobs and retail in, err, Watford High Street. These people would lose out.
The journey time from Watford Jn to Euston via the D.C. lines would be c 42 minutes. All trains would still need to stop at all stations between Watford Jn and Wembley, and Queens Park to South Hampstead. Harrow to Wembley currently has a minimum of 10tph all day.
Without additional slow line capacity into at Euston, or additional platforms there, we couldn’t run many more additional D.C. line services. Perhaps an extra 2tph if we’re lucky. So stations south of Harrow to Wembley Central lose frequency.
Watford Jn to Baker St would be c 47 minutes. Watford Junction to Euston Square (comparable to Euston main line) would be c55 minutes. No one would use it for that journey.
Therefore what we would have is:
* improved connectivity between Watford and London via the Met Line, (that no one would use)
* reduced connectivity between Watford and the D.C. Line (which people do use)
* an increase in capacity and marginal reduction in journey time between Watford and London via the D.C. line - which would still be less frequent and more than double the journey time of most existing ‘LNR’ services on the slow lines (and therefore no one would use it)
* no extra paths on the WCML, and no extra capacity, at all, north of Watford.
* delivered 2031-35
This doesn’t feel like a good use of £4-5bn.
Whereas Phase 1 of HS2 costs £27bn, and provides:
8-10 new passenger paths per hour on the WCML south of Birmingham / Lichfield
3 new passenger paths per hour on the WCML into Birmingham
Significant reduction in journey times to almost all WCML destinations
More services calling at Watford, both for London and the north
Limited disruption to existing WCML services during construction.
In 2026.
Forgive me if I have got something wrong in this assessment.