[nito]

Originally Posted by jmecklenborg

A brand-new HSR line between Boston and Washington, DC would only establish an incremental gain in the existing service from the perspective of those traveling express between the major cities.

My impression of the Northeast Corridor is that it suffers from many of the issues experienced by the WCML and other British mainlines: a mixed-use railway of intercity, regional, commuter and freight services with legacy infrastructure bottlenecks creating conflicts, limits on higher speeds and capacities.

Originally Posted by jmecklenborg

A similar criticism was lobbed at England's HS2. Sure, it'll free up tons of capacity on the existing lines, but people who live along the former mainlines will still want the improvements they've wanted for many years, and with the money and attention directed to the new line, they'll be waiting another 50 years.

HS2 is merely one part of a larger jigsaw puzzle to reorganise the railways across the UK to dramatically increase capacity far beyond the HS2 route. Transferring the existing fast intercity services from the WCML, MML and ECML onto HS2 releases slots that can then be utilised by more local and regional passenger and freight services. Two examples:

• At Euston – the London terminus of the WCML – the departure capacity will triple when HS2 fully opens
• Between Coventry and Birmingham, the removal of just a single intercity train service doubles capacity on this corridor for commuter services

As it stands, the WCML, MML and ECML are already experiencing high-capacity pressures. In the absence of HS2 there won’t be any capacity relief the mainlines and many supporting routes across the UK.


Image source: Department for Transport: https://assets.publishing.service.go...tegic-case.pdf

Originally Posted by jmecklenborg

California HSR is building where there is virtually zero rail service today and so is a completely different situation. Also, CAHSR will integrate local and skip-stop into the high speed line, something that is not happening with HS2, where the line will collect local services north of Birmingham and allow them to run super-express to London.

HS2 will be used solely by high-speed capable trains. Enabling local services to run on HS2 would replicate the problems of the existing mainline routes and mixed-speed operation would certainly limit the ability to operate up to 18tph in both directions at high-speed, especially on the core section. There will be connections to the existing WCML, MML and ECML, but these will be for fast intercity services beyond the scope of HS2 (e.g. up to Scotland on the WCML north of Warrington), which of course could form the basis of a HS3 at a later date.

Originally Posted by jmecklenborg

The big compromise in the HS2 design is that northern trains will bypass central Birmingham instead of run directly through it. It would be like CAHSR bypassing San Jose.

Intercity services to Manchester, Liverpool and Scotland have bypassed Birmingham ever since the Trent Valley Line opened some 175 years ago.

During the design phase, dozens of routes were considered; two (via Birmingham city centre) got past stage two, but neither were advanced beyond stage three. The eventual six shortlisted routes all converged on a route south of Coventry into Birmingham Curzon Street via Birmingham Interchange.

Running HS2 via Birmingham would generate very few benefits, many disbenefits, and be too costly and complicated to deliver. There are three complications which would make such a proposal unviable:

• To avoid excessive journey times for all journeys north of Birmingham, HS2 would have to enter the city from the south/south-east which would necessitate the construction of a staggering 25-30km tunnel (longer than the Northolt and Euston tunnels below London combined)
• There is no site anywhere in the city to accommodate a vast six-platform underground station with 450m platforms on a south-to-north axis; the new Birmingham Curzon Street (which ironically is also the site for the first terminus in Birmingham) is on a west-to-east axis
• Such a line arrangement would make an eastern leg (up to Sheffield, Leeds and Newcastle) incredibly unlikely which would neuter the potential gains on the MML and ECML.