George, the line over Pengra Pass and what became UP's Burns Branch were related, both were part of Harriman's grand plan to weld the UP and SP together during the time he controlled both. Also involved was the revised SP main line up the east side of the Cascades. The anti-trust litigation stopped the SP cold with the railheads of their two lines at Kirk and Oakridge, while the UP continued building west through the Malheur River Canyon until they reached Crane. That line would not be extended to Burns until the U.S. Forest Service made building that line a requirement of the successful bidder for the Bear Valley Timber Sale in the middle 1920s.
I've got more on my High Desert Rails site at the following:
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www.trainweb.org]
Jeff Moore
Elko, NV