Union Pacific rail maintenance train. You can hear this beast coming long before it gets into view. Looks like something straight out of Hades itself. The front sprays water on the ties ahead of the engine as it goes along, probably to keep the ties from catching on fire. The rear 'cars' actually grind the rails to re-shape them back to size. The black smoke, sparks, and ungodly noise had us half expecting Satan himself to lean out of the cab with an invitation to climb aboard!