Why was coal so valuable to early railroads as they made their way west over the Cascades and on to Puget Sound? It gave them a commodity to ship back to the Midwest and Eastern markets most certainly, but I'm not so sure that this was a driving economic force. The northwest was also rich in timber resources and could supply an abundant low cost source of wood fuel for firing the railroad's steam locomotives, displacing the need for coal?. There were sure a lot of wood fueled locomotives operating here.
Photo courtesy Washington State Digital Archives, John T. Labbe Collection of logging and railroad photographs, 1892 - 2010, Darius Kinsey photographer
The above photo shows a wood fueled 2 Truck Climax Locomotive commonly used in the logging industry. Lot's of cheap wood scraps readily available for use by logging railroads.
Photo courtesy Washington State Digital Archives, John T. Labbe Collection of logging and railroad photographs, 1892 - 2010, Darius Kinsey photographer
We can see in the above photo wood stacked and ready to hand feed into the locomotive's boiler as it was needed. If anything, a little easier to feed the boiler with wood than shoveling coal. But wood also had some downsides, not the least of which was a propensity for generating sparks and fires along the tracks.
Photo courtesy Washington State Digital Archives, John T. Labbe Collection of logging and railroad photographs, 1892 - 2010, Darius Kinsey photographer
Even with a cone shaped spark arrester designed to limit problems with fire, this was still a problem and apparently more so for wood fueled locomotives than for coal fueled. But even with wood fuel's advantages, coal was still king for the big railroads. Some potential reasons include:
- Thermal Efficiency - Burning wood generated about 3,200 BTU's per pound of fuel. For bituminous coal, each pound generated between 10,200 and 14,600 BTU's - much higher efficiency than for wood. (For comparison, fuel oil generates approximately 18,300 BTU's per pound of fuel - higher than both wood and coal.)
- Thermal Density - Douglas fir, at a 50% moisture content, weighs approximately 37 lbs per cubic foot. For coal, it is much denser at about 84 lbs per cubic foot.
As a result, burning coal required far less space for fuel storage and boiler capacity than did wood - by a factor of nearly 10x. If you are operating a transcontinental railroad, you need to minimize storage space required and the number of stops required for refueling. Water was already a problem but limiting the number of refueling stops was likely critical - substantially simplifying daily operating logistics.
For logging railroads, however, speeds were relatively slow and daily distances short - and wood was essentially free. Thus we see lots of Climax and Shay locomotives burning wood for fuel.
The fact that we did have coal readily available here in the northwest to fuel both the railroads and steamships connecting us with distant markets, I believe was a big big factor in our region's early development.
p.s. - I am certainly no expert in this subject but I am curious and seek to understand why. I'm sure there were many more factors at play than I have suggested as to why coal was at one time so valuable to our region and way beyond just heating homes. I would love to hear your thoughts.