Blue thunder One of the visceral treats of Montana Rail Link’s route over Mullan Pass is listening to a heavy unit grain or coal train assault the hill from a location near the top of the pass. Many times the train can first be heard blowing for the grade crossing east of Austin ten (track) miles away, and soon you could hear the sound of machines struggling with gravity, waxing and waning through the loops and cuts far below. This westbound MRL loaded grain train was no exception, and it wasn’t your typical hard-working 645 engines drumming away either. By the time it reached Skyline and crossed Austin Creek Trestle, the crescendo of four EMD 567s roared through the valley as the train of mostly blue covered hoppers followed two SD7s, an SD9 and a GP9 working hard as road power. Once the vintage diesels finally passed and worked around the corner into Mullan Tunnel, you could then hear the quartet of MRL SD45/SD40 locomotives in a helper set pushing on the rear. I wish I had a video, or at least an audio recording of the thunderous ascent that took place on this August 27, 1993, afternoon.