chriscooper wrote: In the past when performance and reliability of diesels was much lower than electrics, then it was almost unheard of (Waterloo to Exeter and Kings Cross to Aberdeen/Inverness were the only regular services with significant running of diesels on electrified lines, in other cases either the electrified portion has been fairly short, or it's been a low frequency service), but now Diesels can be and often are more reliable that Electrics
I don't agree. Electrics are considerably more reliable on average. The most reliable trains in the country were the Mk1 EMUs!
In
Informed Sources, Roger Ford states "
Indeed, the SRA claims diesel trains have recently proved more reliable than electric when introduced into service. Good grief!
Take something basic in terms of electric traction, like a CEP or a VEP. They will give you 60,000 miles per casualty. While we shouldn't get too excited about EMUs on airport duties, the Class 332s on Heathrow Express are topping 80,000 miles/casualty. The newer Class 460s on Gatwick Express are starting to build statistically significant mileage and in January were a smidgeon short of their contractual 46,875 miles per service affecting failure.
In contrast, a Turbostar, which has more fleet experience than either of these two electrics, gives between 4,500 and 5,000 miles/casualty. This figure is even beaten by the under-developed Networker EMUs which come in at around 12,000 miles. "
Don't believe the spin about diesels, Roger Ford knows what he is talking about!
chriscooper wrote:
, and can often outperform them (especially comparing a modern DMU to an older EMU),
I really don't think so! The only way you can claim that is if you make the absurd comparison of a very low-powered EMU to a guzzling, wasteful DMU such as the 185s, which are such lardbutts that they are unable to travel at the "Sprinter" speeds on the Hope Valley route due to their excessive weight. It's a daft comparison, as your energy consumption is far higher on the DMU, how on earth is this compatible with the current need for increased efficiency?
chriscooper wrote:
so there is less if any commerical penalty to using Diesels in place of Electrics. When it comes to operating costs, Electrics arn't always cheaper, infact the reason some TOCs have given for using diesels more than electrics is cheaper operating costs.
Source? There's no way diesels can possibly cost less than electrics, however I do believe that the TOCs are overcharged for the electricity that they use by NR. I also beleive that heavy underfloor DMUs such as 185s, Voyagers, etc are undercharged for their track access usage and studies indicate that they cause more track damage than originally thought, yet this is not reflected in the price the TOCs pay.
chriscooper wrote: One important point is that diesel cost fluctuates, wheras the Electric cost is likely to be fairly stable. This means that when Diesel is cheap, it can be more economical than Electric.
Not true, it's just that the TOCs are overcharged for electricity. That does not mean that diesel is more economical!
chriscooper wrote: When enevitably diesel prices rise again, there may come a point where the savings from switching to Electric would outweight the cost, in which case TOCs will very likely consider switching to more Electrics. Even from an environmental point of view, Electric might be clean at source, but it's still got to be generated, and most electricity is generated using fossil fuels. Based on unit weight, plus all the auxilliary loads, a 4 car Desiro will use more energy per run than a 3 car 158, and much more than a 3CIG, so the environmental argument is weak.
I agree that Desiros are wasteful, due to the fridge-like aircon and other factors, and they are far less environmentally friendly than a CIG (SWT doesn't really give a damn about being environmentally friendly), but are they really more wasteful than a 158? If so, only due to the aircon. But I still find it hard to believe, do you have any figures for that?
