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UK trains make their profit on freight, moving mostly at night. And (ahem) subsidy.

I didn’t realise about the speed/maintenance variation, but in retrospect I guess it’s obvious. Thanks for posting that.

The other/related problem with passenger services is that if you crash at 70 mph, everyone dies, the line closes for weeks, and people go to jail.

But if coal crashes at 30 mph, you just pick it up.

I didn’t realise about the speed/maintenance variation, but in retrospect I guess it’s obvious.

Sure at low speeds you are dealing with mostly compression stress, easy enough to deal with. But as speed goes up a train going around a curve starts to impart twisting and bending stresses. Much harder on the roadbed. And wooden ties are out at those speeds, they just can't hold the spikes. So not you have to pop for the more expensive concrete ties.

Also the stress of the train going onto a bridge isn't a slow rolling motion, but at 150 it hits the bridge like a thousand ton sledge hammer. So you have to do a lot more inspections for metal fatigue.

The other problem with speed is the signaling system. The faster you go the longer lead time you need on your signals. At high speeds trains just don't stop particularly well. There is only so much friction a steel wheel can put onto steel rail. So you have to put in a much more complex signal system. The more trains you run the more complex it gets. When you are going faster than two miles a minute and need over a mile to stop life can get very interesting for the dispatchers.

And at anything over 70 mph you can't have grade crossings. Unless you like hitting trucks at 150 miles per hour. So now you have to build the entire railway up on an embankment or in a tunnel. Lots of extra expenses there. That is something that people forget when the say just convert existing rail lines to high speed. There is a limit as to how fast you can go before you end up rebuilding the entire railroad.

Here in Chicago the railroads are heavily patronized and relatively successful. But not because they save gas. They stay under the 70 mph limit so they can use existing freight railroads, reducing the cost to METRA considerably. They avoid the traffic on the highways, which is horrible. And they function as remote parking lots. It only costs $3.00 to park in the suburbs and around $20.00 a day to park in the city.

"But if coal crashes at 30 mph, you just pick it up"

I saw some BNSF aluminum coal cars that wrecked last winter near Bozeman Pass. The picked up the coal AND sent a few cars back to the smelter. I took them at least 24 hr to get the traffic going again over the single track.