Of course it always depends what borders you draw.

I started with steam railways. Of course horse driven railways existed before, but they were of a completely different load class.

I don't know what clinker from salt mines looks like. But I guess it's significantly different from sharp, crushed rocks the NZ article describes. Also the Scottish article says that just some sentences later that ballast had completely different properties those days.

Some ballast has been used for centuries. But not the kind consisting of sharp, crushed relatively coarse rock pieces we know today.

> Of course it always depends what borders you draw.

You seem to be rapidly redrawing yours in a different place all of a sudden.

"It's an exaggeration to claim that ballast would have been used for railway tracks for centuries"

You may well have meant "ballast (specifically sharp crushed rocks as they use nowadays)" but that's a very different statement.

> Some [X] has been used for centuries. But not the kind [...] we know today.

I mean, yeah, truism.

Ah sorry, I thought I had written ballast of the current form. That was my intention, but I failed to type what I had thought.

Otherwise there wouldn't be a point to mention that 50 years ago other, less stable ballast was still in use in some places.

That's a wagonway, the wagons would have been pulled by horses.

Steam powered railways were only widely deployed from the 1830's

> Steam powered railways were only widely deployed from the 1830's

Sure but GP didn't specify steam powered / iron-railed / commercial usage / whatever kind of railways in https://news.ycombinator.com/item?id=36184243.

GP suggested that "ballast hasn't been used on railway tracks for centuries" (incorrect) because "railways haven't even existed for 2 centuries" (incorrect).

Right. I referred to Stockton - Darlington 1825.