Transit in Washington was very similar to that in London; only it was more modern and there were no breakdowns in the tunnels.
One thing that always fascinates me about underground transit is the gentle wind that comes before the train; the wind that tells you the train is coming through the tunnel and will arrive at any moment.
Calgary’s C-train is mostly above ground so Calgarians don’t get to experience this. It’s above ground because the water-table in Calgary is too high and the rock too dense.