Southern Unionist
First Sergeant
- Joined
- Apr 27, 2017
- Location
- NC
Civil War veteran Ephraim Shay (1839-1916) was very unhappy with the state of log transportation in mountain areas, shortly after the war. Rubber tired logging trucks didn't exist yet, and conventional railroad technology was incompatible with remote mountain terrain, requiring sharp curves and steep grades. Technical limitations on trains led by 4-4-0 or the more freight-friendly 2-6-0 steam engines restricted them to 5% grades, but economic limitations limited them to something closer to 3%. This made it nearly impossible to log mountain slopes in the Northeast or Southeast and economically deliver those logs to sawmills, except on lower portions of the mountains where logs could be skidded down to rivers.
Shay's answer to this dilemma was the invention of the Shay steam locomotive, around 1877. Made just for logging, the Shay was (and is) able to climb grades of up to 13%, while turning unbelievably sharp curves, at around 4 to 6 miles per hour. As shown above, in a more advanced design than the original, it has three vertical travel steam cylinders on the right side. The crankshaft powers each and every axle on the engine and tender by way of a long, low driveshaft with universal joints and telescoping sections before / after each swiveling wheel truck, with an extremely low gear ratio for high torque. This design allows easy access to all the high maintenance drivetrain components, for inspection, lubrication, and repair. Also note that the coal bin (yes, coal in a logging area, for space conservation and increased range) is built on a frame extension, while the swiveling tender is for water only.
They are amazing to hear. Due to the gear ratio, when they're coasting downhill at a blistering speed of 8, a Shay sounds like a conventional steam engine doing 60!
Shay's invention revolutionized the logging industry in the Reconstruction Era and well beyond, greatly expanding the acreage economically open to logging, all over the eastern states that are not mostly flat, and out west. Thousands of these locomotives were built, and tens of thousands of miles of logging tracks.
No invention is perfect, and the Shay's biggest flaw was its lack of symmetry. To compensate for all that extra weight on the right side, the boiler had to be mounted off center.
That resulted in a center of momentum and inertia that was higher on the left side than the right, and sloshing water in the boiler also had offcenter effects. As a result, Shays loved to climb over the outside rail on a curve, especially on the right side. Water lubrication of flanges helped somewhat, but didn't cure the problem, especially on low quality tracks that were more or less standard in the logging industry. This led to the invention of two alternate designs.
Before we look at the Climax and the Heisler, we'll look at the rest of the steam logging system and culture in future posts.
In case you want to see these beauties in operation, the Cass Scenic Railroad in West Virginia operates every summer and fall. Nearest civilized lodging and food is at the Snowshoe ski resort. Cass has the world's largest collection of operating Shays, the only operating Climax, and was working on a Heisler restoration the last time I was there.