[gsnedders]

> The speed from the airport down to the depot is pretty shocking, mostly because it takes a whole bunch of ridiculously tight turns.

That's true, though it's only c. 3km of the 14km route. Certainly the 10km/h restriction round those bends makes it seem crazy slow and impedes progress out there. (I originally wrote, though deleted it, a question wondering how big the time saving would be; perhaps a minute?)

The section beyond Murryfield is mostly straight and it does get up to a fair speed between stops, which are mostly about 1km apart. It's the crawl around Murryfield (due to having to take a circular route around the edge of Haymarket (railway) depot) and the curves out by the airport that really kill any feeling of speed, though, no matter how fast it gets up elsewhere.