...It isn’t going to coming back from the mechanical dead.
I’d wager quite a steep bet every single person reading this article has fantasized at least one or twice about traveling back in time and observing the age of steam in person. Most of us also realize that steam, at least to power locomotives, fell out of favor, and we have some idea of the technical and mechanical reasons why it was abandoned.
I say mostly, because I come across articles and web sites arguing for steam locomotives to be brought back into regular service. I don’t mean groups like the A1 trust, which desire to replicate historic locomotives without significant alterations. I am referring instead to proponents of “modern steam,” and I’ve got to get out a rant about this whole idea.
The enthusiasm is admirable, I’ll give them that, but in my opinion, many modern steam proponents have a very poor grasp of how steam actually works is quite lacking. Their mistake, I think, is looking at a return to steam in terms of each individual locomotive. In that sense, a return to steam might seem plausible on paper--but much of the benefit disappears when you step back and try to implement a return to steam as a system.
So let’s step back, look at some of the common modern steam selling points, and then debunk them one by one.
1. Steam can compete if the boiler/firebox is made more efficient.
Only to a point. There’s an upper limit to how much heat you can transfer from the fire, through the boiler material, and into the water, just because of the nature of the materials themselves. You can theoretically increase the boiler length and diameter in order to get more capacity, but in doing this, you end up making the locomotive so large that it is difficult to maneuver and is very rough on the tracks--exactly what began to happen with the latest generation of American locomotives.
But really, that is all irrelevant anyway. Even supposing that you can create a steam locomotive that is just as efficient in terms of performance and fuel consumption as its diesel-powered counterparts, this does not compensate for the fact that a steam locomotive needs to be supplied with water, not just fuel.
This is what I mean when I say that modern steam proponents fail to think in terms of a system: By the time you figure in the cost of trucking or piping in water--which would come at a significant cost in arid regions where water sources are already stressed to the breaking point, and in cold regions where it will have to be prevented from freezing--you counteract all the theoretical savings you would get out of a super-efficient steam locomotive.
2. But we can design a locomotive with a condenser, and then it won’t need to exhaust water!
Highly unlikely. The design of traditional steam locomotive used exhausted steam to move hot smoke through the boiler and heat the water. If you abandoned this design, you would have to compensate with pumps or some other mechanism to move heat through the boiler evenly. This, and the condenser, would eat up the power that would otherwise go towards moving the train.
3. Depending on the fuel, steam can be cleaner than diesel-fueled locomotives.
The idea here, I think, is if you design a locomotive to run on nuclear power or something else that burns with a highly clean fire, which would be desirable over highly polluting diesel engines.
Again, this is a case of thinking in terms of one individual vehicle, rather than an entire system. The fuels that burn clean are often quite dirty when it comes to extracting them from the ground and then disposing of the leftovers. Factoring this in, the “clean steam” become just as dirty, or even worse.
And for anyone who honestly thinks that nuclear powered locomotives are a good idea? No. Just, no. It might work fairly well for well for ships and submarines and power plans, but trains run right through our populated areas and are fairly often involved in collisions and mishaps. I don’t trust the idea of “leak-proof” designs--chance will always throw something at you that you didn’t think to work into the design.
4. There’s a worldwide oil crisis looming on the horizon, which is going to force us all back to using steam locomotives anyway.
All right then, Mad Max.
First of all, the problem with this is that most steam locomotives ran on coal or oil--the exact same fuels that these people are theorizing would return us to steam in the event of a shortage.
With this one, there seems to be an idea out there that you can chuck any darned thing into a firebox, and it’ll power a locomotive. While that’s technically true, there are vast differences in how efficiently and how hot different materials burn.
Wood, for example, can power a locomotive, or farm refuse, but non-fossils fuels have a very low thermal efficiency. The locomotives will consume them in vast quantity, probably too high a quantity when the reset of society has broken down.
Besides this, I wonder where, exactly, these locomotives are going to come from if the Apocalyptic Wasteland finally gets here? Put aside the issue that much of the manufacturing industry has been outsourced. You’d need specialized manufacturing equipment and the people who know how to use it--this kind of work can be very hard for heritage railroads to find--high-quality materials, and the means of collecting and moving the fuel for the locomotives. Much of this manufacturing ability might also collapse, if traditional fuels collapse.
...I have to admit, though, that this would make an awesome Doomsday Preppers episode.