As of May, 2023, the Heisler geared steam locomotive running on the Silver Creek and Stephenson RR in Freeport, Illinois is fired by wood only. I helped load the fuel bunker with wood this past May. In several previous years, the Heisler burned coal exclusively. I was told they changed to wood because it was cheaper than coal and the wood was being cut from trees along the railroad right of way by volunteers. While wood my be cheaper, it contains much less BTUs than comparable volume of coal AND wood is much more labor intensive than coal. BUT, the volunteer staff labor is free and willing to do the work on this small, low revenue railroad. If you are a railfan, this is a MUST see and ride locomotive. They offer cab rides at a VERY reasonable price of $20 per ride.
W H Eccles heisler 3 on the current sumpter valley still is wood fired like it was back in service on the logging line that connected to the original sumpter valley
