Here is some comparative data on emissions.
This is all from 1992
(Trolley Operation Review, Edmonton Transit Marketing and Planning,
January 1993). All figures quoted are g/km. Emissions for trolley
are from gas-fired power plant at source.
HC Diesel 3.5
New Technology Diesel 1.5
CNG 2.2
Trolley 0
CO Diesel 12.1
New Tech Diesel 4.3
CNG 1.7
Trolley 0.06
NOx Diesel 21.9
New Tech Diesel 13
CNG 18.5
Trolley 3.12
SO2 Diesel 1.6
New Tech Diesel 0.2
Trolley 0.012 (don't know where they got this figure; Edmonton
Power states that SO2 is NOT produced by a gas-fired plant. Never
has
been. Therefore, ought to be zero)
TSP Diesel 1.1
New Tech Diesel 0.7
CNG 0.2
Trolley 0
CO2 Diesel 1558
New Tech Diesel 1657
Trolley 1560
CNG No figure provided.
Current emissions from gas-fired plant
are now almost half of what these
were back in 1992, notably with respect to CO2, so trolley is
even cleaner
today. There is virtually no comparison between any of these modes:
The
trolley is clearly the cleanest vehicle going. I find it hard
to believe
that anyone could choose to replace trolleys with NT diesel or
CNG based on these figures. But the interesting thing is the source.
Edmonton
Transit's report cites their source on diesel, NT diesel and CNG
emissions
to be: Toronto Transit Commission Report: Trolley Coaches -- Summary
Report, May 26, 1992. Information originally came from Hamilton
Street
Railway. (Power generation emissions is the only Edmonton data
in the
lot.) Now both Toronto and Hamilton phased out trolleys in favor
of CNG, a
bus on which the data is firstly incomplete, and moreover, what
data there is shows it to be a dirtier bus in some respects than
NT diesel!!!! I
have a number of documents from Hamilton that quite clearly show
the
closure of their trolley system was due to the personal agenda
of some
folks at the HSR, no doubt combined with the desires of some politicians
to boost natural gas sales.