Why is it that when diesel trains don’t use electric pickup even though they could?

Question

If the trains are diesel/electric then surely they could have a pickup to collect electricity from the wire/third rail, where I live there is a railway line which for half of its way is diesel, but the other half is electric (it joins to an electric one) why doesn’t this train use both sources? (It’s the Uckfield – London Bridge Line). I have seen it on French, Dutch, German and Czech railways. Surely the cost of diesel is higher than electricity?

I mean a train using diesel as a fuel EVEN THOUGH it is on a track with electrical pickup avaliable

and that the train is a diesel/electric one; so it uses electric current anyway, apparently the trains on the railway line near to me are "Turbostar"

The track does about 30 miles on electric and about 30 on diesel track; it goes right into the centre of London (thorugh residential areas) so wouldn't it be enviromentally, economically and aetheticlaly better for the train to use electric when in an electric area?

Answer 1

Well, you're talking about Europe there..but in the US the technology has been for almost 50 years, since it was developed.

The New Haven Railroad developed and purchased 30 FL-9's from EMD in 1957 (and another 30 in 1960) that were Electric-Diesel-Electric units. They ran either off their on-board 567 prime mover or from third rail power in New York city. Metro North still has some NH FL-9's, albeit rebuilt.

The modern GE P32AC-DM's used by Amtrak and Metro North are the same principle.

However if you're talking about overhead power, a.k.a. catenary, there is no chance of a D/E also capable of taking power from overhead AC wire.. It would weigh too much, be too large, and a maintenance nightmare.

Answer 2

Very simply, a diesel electric locomotive or multiple unit (which the Turbostars are) use a diesel engine to generate electricity to turn the wheels. That electricity will not be at the voltage that the supply to the third rail is (600volts DC) It is not just a case of that loco/unit picking up power from the third rail and using that 'to turn the wheels' A whole second engine and set of controls would be required. The question is rather not as you ask - why cannot a train use dual power sources - but why won't the investment be made in electrifying this short stub of line lying in an otherwise totally electrified area? There are lots of places where this should be done - York-Leeds and Leeds- Manchester to name but two. But Governments will not invest in rail - even if this Government tries to maintain green credentials (2.5% rise in car fuel duty, 1st for 3 years, 4.5% rise in rail fares, 8th in same time) - New Labour just talks humbug

Answer 3

Turbostars are not Diesel Electric. They are Hydraulic Drive (Mercedes MTU Engine driving Voith Hydraulic transmission and Germinder final Drive). It would be impossible to fit them with electric drive as they don't have electric motors! The Turbostar is a common design throughout the UK with minor details to suit the operators preference. Southern's fleet of diesels is very small. (about 20 trains) The cost of such a small bespoke order would be prohibative, so they are using a pre-existing and proven design.

Of course a better option would be to extend the power rail to Uckfield (and Hastings to Ashford) allowing Southern to have a fully electric fleet.

There is a hybrid electrodiesel locomotive in the UK, its designed to use electric for most of the time with a small diesel engine for working in yards or other places where there is no power rail. But they are low powered and not suited to prolonged working away from the power.

Interestingly Virgin Cross Country and Bombardier (the builders) were looking at adding an additional coach to their Voyagers, which may have been fitted with Pantographs and associated equipment for running on Electric power where it is availible. costs for this would be much lower as the R&D cost would be spread over 78 trains (as well as Hull Trains and Midland Mainline's fleets of similar trains). If the DfT had not intervened with its plans for cutting back Cross Country, the first of the extra coaches would be arriving around now

Answer 4

Same thing here on Long Island, half of the LIRR is electric (Going inbound/westbound into NYC PENN STA.), once it gets to Babylon (about 1/2 way approx. outbound towards the less populated east end) it only can run on Diesel, the diesels can run up to Brooklyn (inbound/westbound) on the electric lines but can't go into the tunnels under the East river leading to Penn Sta (from Brooklyn to Manhattan, so everyone changes at babylon, mostly), I think that they just now have a Diesel electric, that CAN use the pick up off the electric third rail of the tunnels, and go into Penn. sta in Manhattan.