Amtrak's Transcontinental Steam Excursion crests the summit of Cuesta Grade, just north of San Luis Obispo, California, on April 27, 1977. In the process of conquering this grade, the big Lima 4-8-4 knocked decades of soot loose from the tunnel ceilings, making this engine look like the workhorse it is – and making that washing it got two days earlier in Los Angeles seem futile.