DURANGO, Colo. (CBS4) — The 416 Fire shut down the iconic Durango and Silverton Railroad several times this summer. The forest service hasn’t determined an official cause, but a group of Durango residents filed a lawsuit, claiming material from the coal-fired engine started it. That’s prompted the operators to switch some locomotives from coal to oil.

In California, it was oil — not coal — which fueled many of their steam engines. That’s why the locomotive known as the Slim Princess is visiting.

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“We brought it out here so our crews can get tested on it, learn how to drive what is now an oil-fired train,” officials said. “For us, it’s very foreign.”

Randy Babcock is responsible for training the railroad’s crews.

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“Having this locomotive sitting here and being able to sit in it and listen to it and understand it makes all the difference in the world,” Babcock said. “It allows our crews to really get familiar so when they’re on the revenue passenger trains with our own equipment, it’s second nature.”

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Coal has traditionally fueled the railroad’s locomotives.

“The coal mine we use here is 14 miles up the road, and it’s the same coal mine that we’ve used for 137 years,” officials said.

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Now, supply concerns have officials looking for an alternative to coal.

“One of the things we’re learning is fuel types. What blends of fuel work better than others,” officials said.

The lessons taught by this locomotive will be put to use on one of the railroad’s current locomotives being converted to burn oil. The railroad’s historic locomotives are not being replaced.

“We’ll always have coal-fired steam. We want to stress that. That’s part of who we are and who we have been,” officials said.

For now, though, the Slim Princess is being treated like royalty.

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Officials said they get calls every day about when they can ride the train. It will be in Durango through the summer.