On Tue, 23 Oct 2012 16:58:54 +0100, "Arfa Daily" wrote:

On last week's episode of Eddie Stobart Trucks and Trailers, they showed
driver Mark working with a new illegal-length trailer that they have been
given special dispensation to trial on UK roads, by the DoT. They said that
it was called an "Eco-trailer" because being some 2 metres longer than a
'standard' trailer, it would be able to carry nine more cages of Tesco
goods, which would mean less lorries on the road leading to a fuel and
pollution saving.

Fair enough, I thought. But later whilst giving it a bit more consideration,
I started to think about the 'not getting owt for nowt' principle, and
started to doubt whether there really is any 'free lunch' to be had here. If
the 'standard' trailer is about 13 m long, then this one at 2 m longer
represents about an extra sixth of a truck. So for every six of these new
trailers, you'd save one standard tractor unit and trailer. But then, you've
got to take into account that the extra 2 m of trailer is going to weigh
quite a bit, as is the extra axle and tyres that it had, and the extra
equipment to make the rear axles steerable so that it can get round
roundabouts, and manoeuvre in tight yards. On top of that, there will be the
additional frictional drag from the extra axle, plus the weight of the nine
extra cages, and the goods in them. Hauling those additional weights and
losses, is going to take more engine power, and will thus use more fuel. So
how much fuel usage advantage would really be gained from these extra long
trailers ? Any ? Rather less than was implied ? And as for reducing
pollution, I know that diesels aren't the cleanest of engines, but as far as
I am aware, they produce little or no carbon dioxide, which is the one that
the green mist brigade are terrified of, and only small amounts of carbon
monoxide, so is this just another case of adding the word "Eco" to the front
of some existing item, to justify getting what might be a contentious change
to that item, accepted ? Or am I just being cynical in thinking that if
Stobarts got the approval to roll this out across their fleet of
curtain-siders, they would save the wages of one sixth of their drivers ...
?

http://en.wikipedia.org/wiki/Exhaust_gas

says the CO2 is very little different.


--
Regards, Paul Herber, Sandrila Ltd.
http://www.sandrila.co.uk/