I would love to be able to tell our enemies where to stick their oil! But the answer to the issues in your post are more rooted in politics than in rail technology.
We have plenty of oil right here in this country. It just isn't being pumped. Lack of oil is not the problem. Identifying and admitting who our enemies are is the problem. This requires a political solution.
We are literally sitting on the bulk of the earth's coal reserves. Even if we were really running low on oil, there is sufficient coal to provide our petroleum needs for centuries.
Diesel power won out over steam because of the savings in labor and facilities. Only by irrefutably proving that this, could a hide-bound, traditional industry like railroading be convinced to make a wholesale changeover in technology. A reverse of this, going back to steam, would require a similar conversion. Highly unlikely.
The UP tried a couple of innovative attempts to incorporate the two technologies. The first was in the late 1930's, with the introduction of steam-turbine-electric locomotive prototypes built by GE. I don't know why these didn't work out, maybe they were just too complicated to work on.
The second attempt was to build a locomotive that would burn coal directly in a turbine engine. This was two stages removed from prevailing industry technology. The first stage was a turbine engine to power an electric drive system. The second stage was powering it with coal. This engine was a railfan's dream: a Great Northern GE "Big Bertha" electric carbody housing the turbine and generator; a PA-1 carbody containing the control cab and auxiliary Diesel power unit; a Rube Goldberg tender holding the coal and a means of pulverizing it. Can't you imagine a fleet of these monsters? Can you imagine the sound?
Considering this was from a railroad that was known to doublehead gas turbine electrics with 4-8-8-4's, it helps to put it in perspective.
But alas, it didn't work. Fly ash from the coal ate off the turbine blades.
I have to say the solution to bringing back coal-powered trains is to electrify the lines and burn the coal in generating plants to power them. And it doesn't look like we have many lines that could possibly justify that.
No matter what we do, everything is going to become more expensive. It's just a product of history and future demands. The ACE3000 was "supposed" to address all of these problems of coal-burning---maintenance, pollution, and the then-scarcity of oil from OPEC. It was to use coal and water packs similar to a shipping container that could be loaded onto and off specially built tenders with a front-end loader or a simple mobile crane. Computers were to enhance the firing of the boiler for maximum efficiency. Smoke and pollution were to handled with "scrubbers", the which of I am not fully familiar. It was not just another rail buff's dream choo choo, but a real solution to the problem at the time. I do also question the side-rod design as a giveaway and concession to the hopeful foamers who would give anything to see a steam engine in regular service again. I also DO understand the difficulties of coal. Its dirty, it creates pollution by spewing carbon and particulates into the air (it can, however, be controlled in *stationary* applications), and the mechanical limitations that gave diesel the edge were too huge to ignore at the time. In 1979-1982 Norfolk Southern, Union Pacific and others were supporting the research of ACE, so we can't say they would be opposed to steam simply because it is steam. They WOULD, I believe, support serious research into whatever alternate technologies could equal or surpass the diesel loco, with the object being to remove oil as a fuel. Many railroad companies, I believe, still own many coal fields as additional assets. The difference in THEN and NOW is, the price of oil is RISING, not falling as it did in the early 80's, placing a huge burden on the railroads, the aviation industry, and the average person in the price of fuel and all commodities that are either derived from pretroleum or transported by it. Obviously, we need to change our political objectives to either permit the use of our abundant resources, reduce its disadvantages, OR allow our own oil resources to be used to the fullest as well. While I would not wish ill of our foreign brethren, it would be satisfying to see such allies, especially the ones who have enjoyed huge revenues at our expense, have to face the realization that they cannot continue to sell $100 barrels of oil, but, rather, have to do with $25 because the American market and the customers they have gouged and held in disdain for so long no longer plead for a suckle at their teat. For enemies who will us ill, go to the devil!
I know that there other alternatives that don't necessarily involve external combustion, but this attempt at reviving the "old" technology and the research into liquified coal (slurry) stopped when the price of oil fell like a rock, and there was no need to pursue it, and a gallon of gas at the pump was back at .79/ga. But what of liquified coal to burn in diesel locos? Could that help? When the research stopped on ACE3000, there had been NO effort to advance steam tech since about 1956. Even in 1980, computers were being used to control various functions in a variety of industries. When the diesel loco came along, it solved so many problems of the steam engine, it just wasn't even funny. Logically, any research in steam propulsion basically stopped dead. Stationary boiler and steam production for other applications continued, however. Could all the problems of the steam locomotive be now solved with modern methods that didn't exist then? Answer: We don't know. Production of steam in a mobile application or research into such a thing hasn't been pursued. Everything from efficiency to adhesion to safety just quit.
I don't really care either way what technology would be applied, but this has always been in the back of mind. What if................................................... ? How do we KNOW that steam locomotive technology cannot be advanced, or that it could surpass diesel.
I do also know that, as mentioned, advancing a new technology is difficult. Re-starting an old one, even more so. That could be due to old memories and stereotypical response, a reluctance to "regress"(?). But do we really know that we know just because it was inefficient in 1950? Without data, we never will One final item. We talk of environment. What about the visual "pollution" of a maze of catenary? Is THAT not a form of pollution?