Return to Archive -by date - by topic - 2000 Archive.
GNER and Virgin have put it in writing – someone's going to have to deliver a 4000hp diesel
A pox on the Regulator and his footling consultation documents (writes Captain Deltic). A grievous murrain on the SSRA and all its works. The 10 year plan can wait. This month I'm going to start with traction. I'm going to write about rorty 18 cylinder diesels. I'm going to write about 4000hp locos not piddling little DMUs with converted bus engines.
Are you with me? Right, let's go.
East Coast diesel dream locos
GNER - ‘The world's first 140mile/h diesel powered tilting trains
Virgin Rail - ‘225km/h Vitesse diesel train'
Because extending the electric string to cover the length and breadth of the East Coast Main Line isn't on Railtrack's agenda, whoever wins the replacement InterCity franchise will need diesel traction to serve those parts the electric fleet cannot reach. Currently, this requirement is met by the sub fleet of IC125s.
While massive re-engineering is feasible, Terry Miller's iconic 1970s High Speed Diesel Train is now getting on. Anyway, no franchise bidder would risk offering second hand trains, even enhanced IC125s, nowadays.
So, a few years into the replacement franchise, IC125 will become life expired. Replacing like for like would be hard enough. But, to make it worse/more interesting, both short-listed bidders for the franchise are offering quite extravagant diesel trains in their franchise bids.
In particular they are offering, by diesel standards, high power and very high speed. To be specific, 4000hp and 140mile/h.
Now 4,000hp is not all that of a problem. Back in the 1960s, I rode behind a high speed 4,000hp locomotive in the form of the Brush Kestrel.
And in those days the 4,000hp bit was a real problem. Brush, with their customary ingenuity, shoehorned the Sulzer 16LVA 24 into a handsome Co-Co locomotive. But when it was weighed Kestrel turned the scales at a butch 133tonnes – a 22 tonne axle load. This was a bit of a stopper, given that a you-know-what offered only 645hp less (the Kestrel's 4000 was metric hp) on a 16.5tonne axle load.
Despite reaching 102 mile/h on a test run, Kestrel was never a credible high speed InterCity locomotive with that axle load. And Terry Miller, the BR CM&EE at the time was already looking at the lightweight Paxman Valenta as the basis of a new generation of passenger traction for the 1970s.
Today, thirty years on, Paxman's successor to the Valenta, the VP185, will do what the Sulzer LVA24 did and more, but in an all round smaller, lighter, more fuel efficient and less environmentally polluting package. So a 4000hp diesel locomotive compatible with the Railtrack infrastructure, is feasible, as this column has been pointing out for some time.
What I didn't allow for was the 140mile/h service speed offered by both GNER and Virgin in their ICEC bids. In fact, Virgin does not believe it will be economic to raise the line speed on the ECML to 140mile/h, but, just in case, its diesel traction would be 140mile/h capable
GNER, are sensibly, not talking locomotives for their tilting diesels . They are planning to have diesel generator power cars at each end of the train feeding electric traction packages underneath the coaches..
As Martyn Vaughan hinted in 21 st Century Ford last month, think Pendolino, without the pantograph. The Onix three phase drives under the passenger vehicles would be fed with, probably, high voltage direct current from the diesel generator cars. This is known as distributed power and is the easier option for several reasons.
First, unlike a diesel locomotive, a generator car doesn't need traction motors. Second, a 140mile/h loco would need to have the traction motors mounted under the body (Class 91 style), taking up space needed for fuel tanks. Third, the final drives on the axles would be eliminated, reducing the unsprung mass and track forces. And, finally, the generator car bogies could be optimised for low track forces, with no compromises needed for tractive effort and adhesion. Oh yes, and the control equipment would be simpler.
Given that a Bo-Bo bogie arrangement will be demanded for 140mile/h operation, a 4,000hp 80 tonne generator car sounds the way to go.
Virgin, in contrast, has proposed doing it the hard way, in two stages. Their immediate requirement is for a ‘4,000hp diesel locomotive' to replace the Driving Van Trailer on the IC225s.
Virgin expects to run at 125mile/h, which means that a diesel powered Brush Class 89 Co-Co (aka the Flying Badger) would be the logical option, since this would combine a 100tonne loco with low axle loads and track forces. Brush, however, under its present ownership, is doing very nicely building repeat orders of shuttle locomotives for Eurotunnel at £5million a time and seems to have lost the appetite for innovation.
To be fair, even a 125mile/h 4,000hp diesel loco is going to be a fairly high risk design and Brush corporate policy is to build only existing designs. Given a good price and a 30 plus production run, the diesel 89 might be seen as an existing design. But remember that no other railway has been mad enough to try anything similar, let alone the mythical 4000hp 140mile/h Bo-Bo which is the next requirement in Virgin's franchise proposal.
A 140mile/h capable power car for a Very High Speed Diesel Train (VHSDT) calls for an evolutionary approach t6ominimise risk. The obvious starting point is the General Motors powered, Alstom Transportation built, Class 67 Bo-Bo. Virgin has been discussing the concept with Alstom for some time.
As remarked in this column previously, the Class 67 is a bit of a big girl's blouse, with only 3200hp in a locomotive which will add 20p overnight to Jarvis shares if and when it is allowed to run at 125mile/h. But, it's a lot quicker to start somewhere than with a clean CAD screen.
Obviously, the Class 67's General Motors medium speed diesel engine would have to go. According to Informed Sources it would be replaced with the 18 cylinder version of the Paxman VP185 ‘or something similar'. Given that Alstom has just sold its diesel business, including Paxman, to MAN there is no longer an incentive to stay in house.
In theory, the VP185 is a natural first choice. However, owners and operators of IC125 power cars fitted with the 12 cylinder version, continue to complain bitterly about the poor product support from Paxman. Variations on ‘nice engine, shame about the maker' are common.
Still, you would have to be very brave to turn your back on the VP's service experience in IC125, the toughest traction application bar none.
Apart from fitting the new engine, the cooler group, radiator and cooling fans, would also have to be enlarged to removes the additional waste heat. Given that a state of the art four stroke plays a developed two stroke, the increase in radiator size would probably not be pro-rata with power.
Also updated would be the electric traction equipment, where three phase traction could also save some weight and space.
So there is your Super 67 humming away. The next thing is to persuade Railtrack that it can run at 140mile/h without wrecking the track. First, you have to get the traction motors off the bogie and up under the body to minimise unsprung mass and thus track forces.
Then you need a decent high speed bogie. Here Alstom can go to the ‘parts bin' where it has the Class 91 bogie designed by my chum and mentor the late John Dowling.
At this point, the ‘donor' design has a new engine, electric drive, bogies and a modified underframe. With Virgin in thrall to the stylists you had better add an SFE.
Would Alstom sign up to it? Hmm, head and heart time. The head says a Diesel Flying Badger DFB if you must push the IC225s but distributed power for the new generation high speed diesel trains. The heart, not to mention the shade of English Electric's Lord Nelson of Stafford looking over my shoulder says go for the loco.
Head wins, of course, which is why, last month, I assumed that Virgin would go distributed power for its 140mile/h VHSDTs. Virgin corrected me but added 'now you've mentioned distributed power, Roger, thanks for the idea, we'll look into it'.
Still even a DFB would be something for we diesel heads. And in practical terms, the extra reliability could save large sums in penalties paid to Railtrack. Finger crossed.