That is the point;
Suppose we have 4,000 persons per hour who want to travel from London to Leeds, 2,000 persons per hour who want to travel from London to Edinburgh, and 400 persons per hour who want to travel from Leeds to Edinburgh.
Okay, although I will note that I wasn't actually suggesting running all six services through to Edinburgh, I would run six services through to Newcastle, probably extending four of those to Edinburgh/Glasgow, but anyway.
The alternative configuration - as proposed by HS2 - would be to run 4 trainsets London-Leeds direct, 2 trainsets London-Edinburgh direct, and an extra classic compatible trainset Leeds - Edinburgh. All the captive sets would run 77% full, and the classic compatible set would run 80% full.
Right, lets suggest travel times of roughly 1hr20 London-Leeds, 2hr London-Newcastle via Leeds, 1hr50 London-Newcastle avoiding Leeds and ~40m for Leeds-Newcastle.
We will also assume 20 minute turnaround times at both ends of the journey.
This means a set's cycle time from London to Leeds and back is 3hr20, 4hr40 London-Newcastle via Leeds, 4hr20 London-Newcastle avoiding Leeds and 2hr for Leeds-Newcastle.
Running 4tph London-Leeds thus requires 14 sets, 2tph London-Newcastle avoiding Leeds requires 10 sets and 1tph Leeds-Newcastle roughlys 2 sets.
Total of 24 captive and 2 CC sets.
My proposal would run 6tph to Newcastle via Leeds, this would require 28 sets, all of them captive.
So I have only marginally increased crew requirements (which are a major cost) and probably only marginally increased rolling stock procurement costs (roughly 10%? or something as the 400m sets are likely to be similar in total price to the CC sets thanks to the CC sets being horribly bespoke)
But I have generated vast amounts of excess capacity between Newcastle and Leeds, and although I was not actually proposing it originally there is no reason why this could not be extended through to Glasgow via Edinburgh, where you will definitely pick up large flows between Edinburgh and Glasgow.
Now I've picked those numbers to support my case; but they are not far off the numbers in the DfT demand model. Running 6 services per hour (configuration 1) all the way to Edinburgh transports a lot of empty air; and consequently requires many more trainsets to be bought than in configuration 2. That in part is set against not having to buy so many classic compatible sets (which will be a lot more more expensive per seast than the captive sets); but even so there would appear to be a clear answer to your question; we would definitely be better off with the HS2 configuration, if the pattern of demand conforms substantially to the current DfT demand model.
Yes, but running air around on high speed trains is actually very cheap, the marginal cost of a seat between Leeds and Newcastle would be similar to that between London and Birmingham, which is roughly £15
return.
Even allowing for an awful capacity factor you easily beat today's ticket prices and could thus allow for drastically increased demand between Newcastle and Leeds.
Especially as I assume that all services on the HSL would make one intermediate stop between Newcastle and leeds (even if they avoided Leeds), but with 6tph you can give 3 stations 2tph service instead of one, with the additional gains in ridership over the other option.
Mileage is cheap, the major costs are crewing and rolling stock procurement, neither of which are really increased majorly by my proposal.
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Don't think there are platrforms long enough to take 400m classic compatible doubles. 260m (as proposed for the Newcastle services) seems the maximum feasible.
... There are plenty of platforms on the high speed network for running CC services doubled up.
You could run a train to Hull and a CC train to Aberdeen or somewhere in one formation on the core route, so it only uses one path and then split them somewhere like Leeds or wherever you chose.
(And before anyone says anything about disruption it has no more potential to disrupt the network, since if one of the two components is late the network only has to deal with one late train, the same as if they were to run seperately).
But getting 550 seats into a 200m trainset is going to be quite a squeeze; something like the Class 395 Javelin units scaled up. But the class 395 alows no first class, no shop, limited luggage space, and limited space for lavs. That may work well from Kent to St Pancras, but spending 3 1/2 hours on one may be a bit of a trial.
Why the attachemnt to 550 people on a trainset?
A 200m trainset would obviously have fewer seats but its not so few as to render the whole thing infeasible.
As to the double decks, I would be very interested in your views. My own limited experience in Sweden suggest that limited loading and unloading times at turnround could pose problems for double-deck stock. If you have over 1,000 people (some in wheelchairs, others in buggies, and many with accompanying wheeled luggage) all wanting to find their particualr seats on a 400m long train, and only 5 minutes to do it in.
I would propose a pair of travelators on the platform to allow people to spread out more, and since we will be running the same trains over the same route all the time I would suggest marks on the platforms and so on for people, written in various languages ofcourse, especially as it seems the trains will be operated by ATO anyway and thus can be trusted to stop in almost exactly the same place every time.