Westbound local. Clover Valley Lumber Company saddle-tanker #4 runs compass west with a local freight on the Niles Canyon Railway in the low-angle afternoon sun. Clover Valley Lumber #4 is a 2-6-6-2T Compound Mallet Saddle Tanker. She has two complete engines and a chassis that pivots between them. Steam feeds the rear set of cylinders first, and then is exhausted and re-used by the front engine. When the engine goes around curves, the boiler, which is firmly fixed on the rear engine, swings back and forth across the front one. It provides some very interesting photos when it goes around sharp curves. This locomotive is oil-fired and stores its oil supply in a bunker, just behind the cab.
The folks at the Pacific Locomotive Association (PLA) indicate that this engine was a standard offering from the Baldwin Locomotive Works, when it was ordered by Clover Valley Lumber back in 1924. The company offered options for various types of tanks, including a full saddle-tank, a split saddle-tank (such as #4) and a pair of side tanks. Interestingly, examples of all three still exist. This particular engine is almost identical to Black Hills Central #110, which has been running up in South Dakota for many years. The 110 also has the split saddle-tank. The Black Hills Central is also in the final stages of restoring another, nearly identical engine, #108, which has the full saddle-tank option. Tractive effort on all three engines is roughly 37,500 lbs.
The Niles Canyon Railway is a preserved segment of the original Transcontinental Railroad, built by the Central Pacific Railroad in 1869. This segment of track was part of the extension from Sacramento, CA, to the San Francisco Bay Area. It later served the Southern Pacific for 115 years, before being dismantled in 1984. The line was rebuilt by the Pacific Locomotive Association later that decade and is now operated as a tourist railroad.