Thank you Kevin and Hot Water. That explains it really well. It made me wonder if there is any practical reason (apart from showboating for the crowd) why an engineer would ever want to blow black(or grey) smoke.
If there isn't any practical reason, then there certainly would not be any ecological reason for ever eliminating steam engines from mainline service. That means that the only reasons for switching to diesel power were strictly economical. From a purely aesthetic standpoint, steam locomotives were certainly the most beautiful machines ever to grace the world's steel rails. Thanks again.
Other than putting on a show, there really isn't any reason one would "want" to make smoke that I can think of. Railroads were operated as a business then just as now, and if you could save coal on the run, you saved money. Any unburned coal going up the stack was simply a waste of money from management's perspective. Taken to the extreme, Chinese steam crews even as late as 2005 were hand-firing the QJs even though they were stoker-equipped. The reason was that you saved coal hand-firing, and the crew got more money if they used less coal.
Either way though, regardless of how good the coal is, you still end up with cinders. I can think of several times this summer around the 765 and 630 where there was no visible smoke and I got absolutely pelted with cinders. The environment may not mind as long as you are not in a dry area with fire danger, but the lady with her clothes out on the line sure did. Black cinders and white sheets don't mix. Of course, you have to realize that just like everything else, there are different grades of coal, and the good stuff is pricey. Using lesser-grade coal to fire your steam fleet was one of many ways to try and cut cost. That, of course, makes more smoke. Cue more complaints from the lady with the laundry.
As far as dieselization, it was a multi-edged sword. Some reasons were economical, some weren't. The end of steam in China has more to do with the government's perception of being "backwards" with tourists for the Olympics coming to Beijing moreso than anything else. It's cheaper to operate steam in China even now.
N&W proved that on a pure operational basis, steam could compete very well with current diesel technology. The final straw that broke the steam engine's back was the fact that you could run a railroad with considerably fewer people employed with diesels. With steam, you had a bunch of employees both out on the road, and especially in the shops. With diesel, you could survive with fewer employees, and many shops needed for maintaining steam were closed. Economics in the end? Yes. Money tends to be at the bottom line on a lot of decisions.
Kevin
