@Redrobes - my guess is synchronised atomic clocks at both locations so they can compare readings at both places.

The likely next step is for Fermilab to reproduce the experiment and see if they can replicate the results.

And the 60ns is +/- 10ns so that gives you an idea of the difficulty there. The size of the error is not in the measuring apparatus, but I'm guessing it comes from the fact that you're measuring a bunch of neutrinos rather than a single one. It's hard to find neutrinos so you need a bunch. It's also hard to make just one, so you get a set of them. Now a bunch has a size and you're never going to pick just one out of there. So the length of the bunch will relate to the error on the arrival time measurement.

@cantab Yep there's nothing wrong with things going faster than the speed of light. Tachyons are totally legit. But we can't make them and send messages with them - or certainly not until now. The hard and fast law is that you can't go from over the speed of light to under the speed of light. You're on one side or the other. Now neutrinos are massive particles but are so light they go close to the speed of light. Measuring exactly how fast is tricky. The supernova measurement was a good check that they actually travel at almost exactly the speed of light. But yes, tachyons would be a good first go-to as it leaves relativity intact.