Have you ever seen a train that can lay its own track? This is an incredible piece of engineering, it makes me wish we had a better train system in Cincinnati. At least we’ll have some sweet streetcars soon. Here is some fascinating information about the track this train is laying (via a comment from reddit.com)
The train you see in one of the last sections, the one with the part that can stand still, is brilliant. It’s an amazingly strong machine, and it’s laser guided. It picks up the rails. Then vibrates the stones underneath the track, so that they fall into eachothers gaps. The stones have sharp corners, and if they are that tightly organised, the bed of stones is stronger than concrete, plus you can still adjust it at any time. If the stone bed is good to go, the machine placed the rails in the stonebed. It does this very precisely, with a less than a millimeter accuracy.
In the dutch and belgian railway system, there are no gaps in the rails anymore between stations. The rails they use are welded together to beams of tens of kilometers long. With this machinery, they can layout the tracks so tightly, that the rails won’t even move when it extends or contracts on warm days and cold nights. The rails simply cannot go anywhere. This is why they spend so much effort on getting the stones right.