CHEYENNE, Wyo. (AP) — One of the largest steam locomotives ever built is coming back to life. The Union Pacific Railroad plans to restore an engine known as a Big Boy. It was a 6,300-horsepower monster designed to drag heavy freight trains over the Wyoming and Utah mountains.

Twenty-five Big Boys were built for the Union Pacific in the 1940s, but they were pushed aside by more efficient diesels by 1960. The railroad plans to restore Big Boy No. 4014, which has been on display at the RailGiants Train Museum in California.

It will be towed this month to Cheyenne, Wyo., where the work will be done at Union Pacific's steam shop. The project is expected to take three to five years. After that, the locomotive will be used to pull special excursion trains.

The tentative schedule for Union Pacific Big Boy No. 4014, which is being towed from Southern California to the railroad's steam shop in Cheyenne, Wyo., for restoration:

April 28: Bloomington, Calif., to Yermo, Calif., passing through Canyon, Victorville and Barstow.

April 29: Yermo, Calif., to Las Vegas, passing through Kelso, Calif., and Jean, Nev.

April 30: On display in Las Vegas.

May 1: Las Vegas to Milford, Utah, passing through Moapa and Caliente, Nev., and Modena, Utah.

May 2: Milford, Utah, to Salt Lake City, passing through Clear Lake, Delta and Stockton, Utah.

May 3: On display in Salt Lake City.

May 4: Salt Lake City to Ogden, Utah.

May 5: On display in Ogden, Utah.

May 6: Ogden, Utah, to Rock Springs, Wyo., passing through Echo, Utah, and Evanston, Granger and Green River, Wyo.

May 7: Rock Springs, Wyo., to Laramie, Wyo., passing through Wamsutter, Rawlins and Medicine Bow, Wyo.

May 8: Laramie, Wyo., to Cheyenne, Wyo.

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