How Green is my train?

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How Green is my train?

Archive - Originally posted on "The Horse's Mouth" - 2010-08-07 22:53:45 - Graham Ellis

The other evening, I was asked if I had figures that compared the CO2 emissions of a train and a bus. Well - I had seen diagrams that showed that a train is significantly better per passenger mile, but I didn't have the figures. I do now:

Train - 60g per passenger km
Bus - 89g per passenger km
Average car - 133g per passenger km
Domestic flight - 158g per passenger km

See Basis of Calculation (using Defra and DfT figures).

But those figures are simplified, I know. A train that's running with just a handful of passengers will have a significantly higher figure - indeed, I think I've seen it said that if a train was carrying just 8 passengers, there would be less emission if two taxis were used. And as you get to faster trains with more wind resistance, there will be an increase too - see [here] - not a train link but a car one, and a similar shaped curve will apply.

Older trains will tend to be less efficient too - the re-engining of the 125 fleet of First Great Western is said to have reduced fuel consumption by 15%, CO2 emission by 64% and smoke by 42%. And if one looks at that 64% figure, one has to wonder if the quoted 60g per passenger km is for the latest modern train, or a fleet average. What further improvements could be made by updating some of the trains that are 30 years old, or by electrification? Yes - I am aware that electiriction does not necessarily remove very much CO2 - done badly, it would simply move the generation from on-board to a remote location.

Something like 40% of the Co2 emissions for each and every one of us relate to personal transport ... and choosing a mode with less emissions from the list above can made a big difference. But that pales into insignificance when you look at other changes that could be made - such as increasing the average loading of cars (currently under 2 passengers), and replanning our lives so that we don't have to travel so far in the first place.