Railfans love railroads, because railroads are the most environmentally friendly way to move a lot of very NOT environmentally friendly stuff.

Oil.
Chemicals. Including the kind that'll kill you pretty quickly.
Cars. Yes, dirty bad cars - what would railroads do without shipping cars?
Steel. Rubber.
COAL.
Dead Trees.

Furthermore, railfans love to bash environmental rules anytime they would cause a railroad to actually be environmentally friendly, but at the same time proclaim how wonderfully environmentally friendly railroads are (just as long as you don't live near a railroad, live near a railroad yard, are standing next to a diesel locomotive, or are near the tracks when one of those bad chemical trains derails and forms a toxic cloud.) But, but, one freight car carries the same as four trucks!