Re: But that would presume that you make no stops.
My route guide says 6 stops between Manc and Brum. Give them 5mins stopping at each that's another 30mins on top.
It's not just dwell time - it's the deceleration/acceleration curve. This is why electrification often cuts journey times - electric traction tends to offer better acceleration than diesel (or diesels geared for acceleration have a lower top speed).
And then there's the notion that the WCML is actually 125mph. Sure, that's the notional top speed, but there are tonnes of Temporary Speed Restrictions for bits of tunnel, bridge, urban approaches or Switch & Crossing (S&C) that were too difficult to upgrade. Most of the southern end of WCML through Milton Keynes is max 110mph. If you're travelling late or at weekends and there's a possession on a fast track, trains could end up on the 70-90mph tracks. So any calculation based on 125mph is fundamentally flawed. North of Birmingham, the "express" lines through Stoke-on-Trent mostly top out at 70mph. There is a bit that's notionally 110 but if you've stopped at Stafford you won't hit 110 before going back on the brakes. Even if you were to charter a private, non-stop service from London to Manchester, you'd end up slowing down to 40mph through Stoke because even without stopping in Stoke, there are 40mph TSRs on that line. Even the big, open Trent Valley line is mostly 110.
And this is why simple new-build of HSR for inter-city services which is actually designed for 220mph is cheaper, less disruptive and easier than trying to torture another few mph out of Victorian alignments. Leave the legacy lines for local & regional services (which only just bounce off 90-100mph before they're decelerating for the next stop anyway). You cut your maintenance costs as well by not smashing up the tracks with heavy IC trains running at full tilt.
That's important because studies by Lithuanian Railways show that capacity (how many trains you can have up a track per unit time) is driven by the difference between the top speed of the fastest and slowest train. Want faster trains? Don't lower the top speed of the fast ones, raise the top speed of the slowest. My point is the top speed of the slow passengers is already at the limit of standard signalling IE 125mph.
Track utilisation is absolutely driven by the speed differential - but average speed. A 125mph local train will have a much lower average speed than the 125mph express train which doesn't stop. Which is why local trains have been edged out by rising line speeds - the average speed of express trains has gone up (because they spend most time at top speed) but the average speed of local trains hasn't - because lifting their top speed doesn't change their average speed much (electrification does massively, because they accelerate much faster and therefore spend more time at max speed). In Lithuania they may have seen this improvement if they had very slow older Soviet-era diesels and replaced them with much quicker stock (which probably also accelerate a hell of a lot quicker than anything pre-1990, especially if they've electrified).
Obviously local trains with faster acceleration and higher top speeds will help minimise that gap, but if you raise the line speed from (say) 90mph to 125mph, the gap between local and express trains will always grow, even if you upgrade both the fast and "slow" trains to have an equal top speed.
It is also overly simplistic to say the top speed of the "slow" passengers is at 125mph. None of the WMT services between London and Brum or Crewe are good for 125. The Class 170-172 Turbostars notionally cap out at 100mph as does the Class 196. The Electrostars are also set up for 100mph and will get there much quicker. The newer EMUs like the Class 397 and 730s are good for 110mph. This probably doesn't matter though, because most of the WCML isn't actually good for more than 100-110mph and even on the 125mph bits, you lose time accelerating from/decelerating to the TSRs that bound that quick stretch.
As you say, increasing freight speeds is a huge driver - even going from 70 to 80mph lets them play in traffic much easier. This however requires electrification, which successive governments refuse to commit to. Electrification is not just for speeds, but for handling grades - diesel locos can suffer grade-fade and need to hit an incline at a minimum speed to ensure they make it up. With electric traction, hills melt away and they can stay closer to their top speed much more easily.
Incidently the WCML upgrade debacle happened because the government of the time went nuts and moved from an average of 9km/year (during the previous 16 yrs) to a total of 2000km+ of
electrification and WCML (as one of the last projects) was at the end of the queue for staff.
IIRC, they also spent a lot of money trying to do ETCS/In-Cab signalling before they realised that trying to "big-bang" that on Europe's most complex bit of railway was a bad idea and scrapping the lot. Which was why they abandoned 140mph top speeds for the Pendos (for those unaware, you really can't do >120mph without in-cab signalling because track-side signal boards whip past too fast).
Elapsed time 20 years minimum. There is something seriously fu**ing wrong with large project initiation and management in the UK.
And BTW in the UK £38m is considered a reasonable price for 1mile of road but governments go into meltdown if electrification costs > £1.5m mile for rail.
Could not agree more. It is insane that that road projects are uncritically waved through (£1Bn for the Black Cat roundabout upgrade anyone?) but rail projects need to spend almost as much on feasability studies as they do on the f-ing build.
However the solutions they (eventually) developed are now on the shelf and were deployed in spectacular fashion when they avoided the rebuilding of an entire bridge in central Cardiff, saving around £40m. The #1 Lesson Learned? Commit to a sustainable electrification programme (as the Germans have since the 1970's and Scotrail has for at least the last decade).
The problem is... learned by whom? Part of the problem we have, is that instead of committing to a rolling programme, our special boy Grant Shapps (albeit only one in a long line of bad transport ministers) was very keen on being "agile". Don't just electrify a line on a rolling basis - surely it would be better to chunk it up into smaller contracts for... reasons. So one contractor comes along and develops solutions for electrifying under bridges (the same design of which will have used along most of the line, because they were usually built by one company back in the day), and then the next contractor comes along and reinvents their own solution for the next block of work instead of having a team who work out how to address the vagaries of <particular line's architecture>, solve the problem once and then do that all the way along.
We knew how to do electrification. We could come up with cheap solutions - the Selby Diversion was delivered as a 160mph-capable electrified alignment on-time and on-budget (despite working over ground conditions that civil engineers call "firm porridge") because the government gave the engineers the green-light and got the f- out the way. There's a lesson in there somewhere.