In the defense of emissions from coal burning, historic steam locomotives, I would concentrate on perception more than on facts. It is perception that is the adversary. The only thing that will win a battle against symbolism is another symbol. Regardless of the facts, defenders of smoking locomotives will always be vastly outnumbered by people who will fail to see any merit in the perceived emission transgression.
It will do no good to justify locomotive smoke on the basis that pollution is produced by many other sources. This is because all of those other sources are readily seen as problems that must be ultimately remedied by ever tightening laws and standards. Thus comparing locomotives to those other pollution sources will merely acknowledge that locomotives are also a part of the problem, and therefore must be brought into compliance just like any modern car, bus, truck, or bulldozer.
Rather than go down that road, it would be far preferable to organize around the principle that historic steam locomotives are few in number, and not significant a significant source of air pollution individually, or as the entire group, and therefore, they should be exempt from emission regulations because altering them would destroy their historical authenticity. This message should be reinforced with a concerted effort to eliminate the premise that smoke is part of the show, and to reduce smoke by the use of the cleanest possible coal, coupled with the most skilful firing. This entire package of information should be actively marketed to the public as a bulwark against the gathering cloud of pollution politics.
RK
