Not saying this as a negative thing. Because having well paid, healthy and rested employees looking after stuff like maintenance, safety, stuff like trying to stop the train when some idiot parks the car over the tracks, or when a badly loaded rail car breaks loose and derails suddenly, or just generally driving in places where fully autonomous operations can’t happen for various reasons.

But it’s the Unions. World wide one of the major things train worker unions have pushed back hardest on is smaller train crews for both passenger and freight… and it should be obvious why. It means companies that move to smaller crews would lay off union workers.

Plenty of this is actually justified by good arguments put forth by the unions, particularly in places like America where railroads have basically refused to spend money in capital expenses and try to run with the oldest railroad hardware possible in order to maximise their profits per ton per mile shipped, regardless of environmental impact, crew fatigue, or the long term degradation of the entire strategic value of a national rail network that can move the heaviest military goods efficiently in times of war.

You could not physically do automatic freight rail in America without getting people killed. The hardware and infrastructure are literally not capable of it. For all the automatic signalling systems in place, it’s all duct taped together around having a human in the loop that can be made responsible for decision making in the train driver cab.

In more modern environments like say Switzerland, they probably could get much closer, but they also have a well regulated railway system with incentives that ensure the companies don’t need to be so brutally effective to make enough money to meet corporate profits. Then there’s places like the trans Siberia railroad… good luck keeping an automated network of that size operating within safe automatic bounds over winter, or the parts of the UK where there are still physical mechanical based rock fall “sensors” in place to alert drivers to their being rocks on the track ahead that may have only landed there minutes ago… and they don’t run enough trains on the tracks to make maintenance of network of cameras and motion sensors worth it.

Railways are, when run well, very automation friendly environments. But that breaks down the further you get from a tidy metro area and surrounding country/farmland, further out into long stretches between cities or states where you would need to maintain thousands of kilometres of fences to avoid accidents, loss of property (stray farm animals) and the larger the network gets the harder it is to have it all owned and operated by a single company that could even begin such a project… sometimes you have a nationalised owner/operator but then it’s government budgets deciding if the actual rails and signals need the upgrades vs the potentially private companies that may own the trains and haul freight on the government’s rails…

The real world is messy. So the union does kinda have a solid point. But that doesn’t eliminate the fundamental fact that at the “big moving objects on continuously welded rails” level of controls theory, railways are very automation friendly and are in theory able to be nearly fully automated.