Leave it to Charlie to put me straight!
After an exchange of emails with Jerry Day, I need to correct my original comments. Yes, there were both narrow gauge and stand gauge tracks between Malta and, say Pando, on the north side. But
it was not 3-rail; they followed different alignments. In fact, in the Pando Valley, where Camp Hale was later located, the standard gauge track took a more or less straight shot down the west side of the valley (the current alignment), while from the pass north, the narrow gauge began to wander about the countryside like a drunken sailor, eventually following the eastern wall of the Pando Valley. Some of the narrow gauge right-of-way could be seen near the very top of the Pass when I was last over that way, but in the Pando Valley, the narrow-gauge right-of-way had been obliterated by the massive rearrangement of the valley floor during the construction of Camp Hale.
Mike