fredag 8. mars 2013
Solutions, Solutions HST-2
I have a pretty clear view on how HST should be replaced.
Firstly I am not disagreeing that HST 1 upgrade is a good idea. It is however a bit typical of many rail companies not wanting to commit capital investment on a scale the public would and blaming short licence periods. However HST1 upgrade could be equally well achieved by a different means which would give the rolling stock more flexibility for use under 25kv wires. More on that soon.
But we need really not just one type o HST -2. Why? Well we have the pending electrification of the GWR which will render a large part of any new fleet obsolete. Also HST 125 was never all that suitable off the GWR; MML; ECML and latterly WCML. THe single main restricting factor was the legnth of the sets, which precluded their use at several major terminii and a large proportion of platforms across the network. They weren't designed for stopping services but is the amount of first class and the restuarant-buffet vehicle really still relevant?
Also of importance is the fact that the train doesn't tilt of course which may seem like a given no-can-do, but in light of the snail pace of super-high-speed routes in the UK (HS1 and HS2 maybe very much later) if the UK and Scotland want radically faster services which can out-compete car journeys and compete with medium distance flights then there will need to be diesel powered tilting trains.
The aim is realistically to be 15- 20% faster than current intercity services IMHO. This means 12 minutes per hour which means for example running at 100mph average instead of 75mph or 120 instead of 100mph. Average speed overall journey, and pick up time from stops are the key two factors to consider. Peak speeds help of course the average but there are always sections and diagrams which allow for some peak speed for a non tilting train. So journeys which currently take an hour and a half come down to an hour and 12 , but it is more noticeable when you break down the hour service and the two to three hour service. Take Glasgow or Edinburgh to Aberdeen: an ideal situaion for tilting trains.
However first and foremost we need to erradicate the additional subsidy stops on routes. Reducing these or even going non stop gives you a 5-10% better timetable diagram on even one hour services. So then you only have to run 10% faster on average and you can do this by tilting at 60mph on 50 mph bends for example it doesn't need to be all over 100mph stuff or vastly out of safe signal-stop distances.
Now we cans start to look at a smaller tilt which perhaps allows for a wider body or less mechanical equipment for the tilt, and an easier tilt for the 80 tonne diesel electric power cars.
And I think the answer has to be in using powercars for tilting trains and locomotives for wide bodied standard trains. Multiple units have nearly all had their issues compared to the best of the post war DE locomotives in terms of performance and reliability and also in the hidden respect of capacity reduction which was a sneeky side effect of moving away form drawn-rolling stock.
The most important aspect of using locos / power cars is that after you electrify a route, you can remove then and place in AC motive power. The locos can then be cascaded to other non electric routes, and in the case of tilting powercars, they can be coupled to new built stock to extend the trains to other non AC routes or indeed they can be designed in outset as convertable to AC drive with removal of diesel power units being lighter than normal locomotives anyway.
Tilting should have been ideal for the voyagers, but that is another story. It is an ideal solution transpennine, far west, MULE and ScR to taking 30 minutes off a a current two half hour journey.
The GWR and routes like the N.Wales and Midland and Great Eastern whcih are still largely not AC, lend themselves though to high speed non tilting stock which by in large has more capacity for passengers and their luggage. Coaches can be longer and wider and have more luggage volume above seating.
Now that GWR to Cardiff at least will get wires, it seems obvious that proven technology should be applied with mark 4 type stock or an updated , light mark 3 like stock being developed. On top of this you would either place a 4000 hp single power unit ie LOCO, or HST type power cars and then you replace these sets with DVTs at each end and a twin power car PSO in the middle of the set, or leccie loco at the end allowing for swap of loco and through services to the west or flexible rostering on the Bristol-Birmingham-Oxford-London triangle with swapping of motive power as needed.
Glasgow Edinburgh is often hailed as a route begging for super high speed trains, but really many of these routes just dont need it: Manchester to all the northern cities needs only the 10% acheivable by less stops and further 10% by tiltign OR line improvements IMHO. Glas-edinburgh needs only electrification, certainly not tilting at 100mph - the route needs capacity and reliablilty and this could even be done with refurbished 318s!! A ten percent improvement is all that is needed really in terms of the wider picture of need-cost-benefit: do we need glasgow -edinburgh in 20 minutes? No , the car journey centre to centre takes well over an hour on most days so a 38-46 minute journey will be ample and proabbly have a far lower carbon footprint than sparking stuff over at 120mph peak.
It is more routes like Liverpool/Manc- Newcastle and those NW cities south to Bristol , the same in Scotland with Aberdeen and Inverness services which can gain big wins over cars, where current flight travel is marginal.
What I am then saying is that it is indeed horses-for-courses : the GWR and MML need long, high capacity rolling stock with 140mph maximum built in for the near future. Also this solution must allow for redundancy of diesel when wires come uip, but also allow for hauling of through trains to the west. Transpennine, far west and Scottish 2 hour plus services need a tilting diesel solution.