It's a busy morning (for Union Pacific's Ayer Subdivision that is) in the remote Palouse River Canyon of southeast Washington. While we wait at our clifftop vantage point, we can hear the sound of the approaching train waxing and waning over and over as it goes in and out of the tunnels to the south of us. The third train within 2 1/2 hours, a northbound empty potash train, is seen working through the heart of the canyon's "tunnel district" as it pops out of Tunnel 13 and is just a moment away from entering Tunnel 14. In a few seconds, the train will be simultaneously passing through five tunnels. I don't think I will ever grow tired of this canyon in springtime green...