10.08kg
Distance York to London is 280 km
"Heat" by George Monbiot , (Penguin 2006) gives
p146. Quotes a parliamentary answer for Co2 from different modes of travel
from London to Manchester for each passenger
Car 36.6 Kg Co2 (1.56 passengers)
Train 5.2 Kg Co2 (70% full)
Coach 4.3 Kg Co2 (40 passengers)
Times Online
http://travel.timesonline.co.uk/article/0,,17471-1454744,00.html says
"Travelling from London to Manchester, a distance of 181 miles (290km), should
be straightforward but often it is not. "
The above can be use to give values for Co2 per passenger kilometer
Car 126 gm Co2
Train 18 gm Co2
Coach 15 gm Co2
Is this optimistic for high speed passenger trains?
But this gives a resulting CO2 emmissions of 10.08 kg ( 280 * 18 g) * 2
Result: "CO2e 10.08 kg"