I don't know what share of that railroad Buffet owned, but it went bust. If I recall correctly, Buffet is invested in BNSF, an American railroad.
The big hit here is to place the public focus on the one working transport mechanism that hauls most of the crude oil from the Williston Basin (Bakken/Three Forks oil). If the transport mechanism is shut down by popular acclaim, some 750,000 barrels of oil a day won't make it to refineries, and a huge economic light will be extinguished.
People have come to North Dakota from all over the US and beyond to work in the oil industry or related good paying jobs, but it could look as dismal as other parts of the country if they can find a way to shut it down.
Don't know squat about railroads. But, isn't their something like chocks that can mecanically lock railcars. Leaving an unattended engine seems nuts to me.