Per Wikipedia:

The line follows a 6-mile stretch of historic right-of-way originally constructed to haul sugar cane from the sugar plantation fields in Kāʻanapali to the Pioneer Mill in Lahaina.[1] At one time, the island had over 200 miles of rails connecting the sugar plantations to the mills. Trucks, however, largely replaced the railroads by the middle 20th century. In 1969, A.W. "Mac" McKelvy and the Makai Corporation created the railroad in order to illustrate this part of Hawaii's past.[2]

On July 24th, 2014, the company announced that it would be closing on August 1st, 2014 due to a financial decision by the owners. The company was planning to remove the tracks and sell them off.

Within months of closing, the Sugar Cane Train was bought by a local Maui resident and is in now the process of being revived.