Heisler was a minority player in the geared steam locomotive market, but its product was sometimes favored in situations where a particular logging railroad had a relatively longer haul, because the design could offer relatively higher speeds while still maintaining good flexibility and the ability to absorb irregular track.
The Cass Scenic Railroad has a fine 3-truck example. Here #6 is seen on the currently isolated line segment that runs out of Durbin WV towards Cass along the Greenbrier River. The line has been severed for many years by washouts, but now current owner Durbin & Greenbrier Valley is working to restore the line. In the meantime the railroad offers short excursions out of Durbin on the "Durbin Rocket". #6 serves as the current power for the Rocket, having been trucked in from Cass via the winding West Virginia mountain roads.
Cass Scenic RailroadFuture TPOTD