"Gravity Hill" is something the Antonito Boys came up with in the last few years. I never heard the term until I left the C&TS. The funny thing is the grade there is considerable less than other spots between Antonito and Lava. I remember the first time I fired west out of Antonito. We swung around a curve down near MP 488 and I looked at that track climbing up the side of the mesa and thought "that's steep, I'd better get busy......" So I got down on the deck and built a big barn burner in 487 only to have it immediately pop off. It is a serious optical illusion. The entire topography is sloped close to a 1.5% grade, downward toward Mt. Blanca and the valley. The top of the mesa slopes down, and the track is climbing up on something about 1%. Once you get around the curve at the top, you have to pull harder on the Lava.