Burning Coal On The Oregon Short Line

This page was last added on May 3, 2016.

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"I have a drawing made by a local artist of a steam locomotive being loaded with wood fuel near Minidoka, Idaho. It is a great drawing, but I don't believe wood was used on the OSL in Idaho, but I don't know for a fact. Are you aware of wood fired OSL locomotives operating in Idaho?"


Oregon Short Line was built across Idaho in the 1880s. By that time, Union Pacific had discovered coal in both Wyoming and Utah, and was shipping coal all across its system for sale to businesses and consumers, and for use as fuel in its own locomotives. Even the earliest photos of Utah Northern narrow gauge locomotives show them as coal burners, due to the availability of coal in Utah.

The coal mines at Rock Springs, Wyoming, were opened in 1868, and were the sole source of coal as locomotive fuel on Union Pacific until other mines were developed in Utah in 1870-1871. Both Nebraska and Wyoming were essentially tree-less plains. There was more large trees available as construction moved across Kansas. Wood as fuel came from growths of softwood trees, mostly cottonwood, along the creek and rivers, and was scarce from the very beginning. Coal as fuel was used as early as 1868, but had to be shipped from coal mines in western Iowa, then ferried across the Missouri River, at least until the bridge was completed in 1872. According to the book, "History of Union Pacific Coal Mines, 1868-1940," as the civil engineers moved across Nebraska and Wyoming in the early years of 1864-1866, they had specific instructions to locate a usable supply of coal for use as locomotive fuel. It was not until Rock Springs was reached that a reliable source of coal was found, and the coal mines there were formally opened in 1868.

The cost of shipping coal from Iowa was $4.50 per ton, including $2.50 per ton to ferry the coal across the Missouri River. When compared to the cost of wood as fuel, reported as $6.50 per cord, coal was much cheaper, and much more efficient as locomotive fuel. By 1875, Union Pacific's locomotives had consumed 148,877 tons of coal, at about 5 tons per locomotive tender at each refueling location. That is over 29,000 tender loads of coal as locomotive fuel, over a period of seven years. Compare this with a similar 1875 figure of having burned 7,137 cords of wood.

More interesting comparisons come from John H. White, in his landmark book, "A History Of The American Locomotive, Its Development: 1830-1880." On page 86 he shows that one ton of coal was equal in its fuel value to 2-1/2 tons of wood fuel. These figures help explain why Union Pacific was looking for a source of coal fuel as soon as construction started in 1865.

So, any photo or drawing of an OSL steam locomotive would likely not show it with wood in its tender.