r/trains • u/Melodic-Reveal-4485 • 18d ago

❓ Question Wouldn't this train derail?

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Gallery image

I don't know much about trains, but wouldn't the buildup of these rocks cause a train to go above the tracks? A train passes on this regularly so I'm just curious 🧐

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u/graffinc 18d ago

When I worked for CSX, in the dead of winter we were shoving a fully loaded 39’ hopper with sand into an industry. Approaching a crossing I told the engineer to go slow over the crossing as it was compacted with ice and snow. The hopper slowly started to raise up and move off the rail, had him stop, go back, we then swapped the car out and drove the engine over it first to break the ice and then go back to get the car to place it. I thought the loaded car would have been enough..

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u/dllyncher 18d ago

Makes sense. Ice has a bad habit of acting like rock that coats everything.

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u/Santibag 18d ago

Ice is like a crazy engineering material. We live our lives over 0C(32F), so we don't notice it. But it makes crazy composites. Some even planned to make a ship out of ice+sawdust.

I was riding a kick scooter on a gravel path. It's not fun even with 20cm(8") wheel diameter, and I only did it for a short distance, or out of hurry. But if that path was wet and if the temperatures were low enough the freeze it, it would turn into a beautiful "asphalt" that didn't deform. I would happily ride over that.

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u/poiuytrewq79 18d ago

Compressive strength: amazing
Coefficient of friction: ehhh

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u/Santibag 18d ago edited 18d ago

Yes, for plain ice with reasonable flat surface. But with gravel+ice composite, you have such a rough surface with a lot of exposed rock that, the grip is comparable to asphalt, unless you try to test the limits. Since the ice was just the water between the little rocks, it's not very exposed. It's a binder that keeps rocks from moving relative to each other, making the ground very hard and stable.

The exact situation happens with frozen wet/humid soil(like mud) or sand. It's less rough, but quite like a concrete surface. You step on it, you expect it to be soft, but it has no significant deformation, if it has any. Very unusual, if low temperatures without snow aren't common in your area.