What do you mean "hard wired the white to black"? Are these the same wires that measured 10V between them? Is your Maestro dimmer paired with another one? If this dimmer is the only one feeding the lights, and you measured the voltage there and it's only 10V, then it's the circuit, not the track lights.

Re-reading your statement and my answer, are there two black wires, one being from the breaker and one to the track? If that's the case, then the white is irrelevant. Get a plain switch and connect the two blacks to it. What's the Voltage between the source black and the white?

Well your screwing around with the wiring probably doesn't help. Usually the failure is where the spring loaded connectors meet the track. If all the fixtures failed at once, it's almost certainly the one where the power feeds the track.

Now that you ask, I see that what I wrote doesn't make sense. So I opened up the box again to reassess the situation.

There are two switches in the box, with one NM cable in and two out to different sets of lights. (The other circuit works fine.)

All the white wires are tied together, and I didn't touch that. I removed the Maestro switch controlling the non-functional lights, and disconnected the two black wires from it.

(I used the meter to measure the voltage across these two black wires, which I now realize was not a useful thing to do.)

To test the track light rather than the switch I then directly connected the two black wires that had been connected to the switch. After turning on the breaker the track lights stayed off. (The lights on the other switch came on.) This tells me that the problem is not the switch. It has to be downstream - the track or the wiring to/from it. But what can go wrong there?

I'm having a similar problem with a Juno track light I am in the process of getting to work. When I first started, the connection between the end feed and the track was intermittent - wiggling it would make the lights flicker. I still haven't a permanent solution; the dealer hasn't answered my query. Where is your track fed? Can you open up the box there?

There is an ~3" long piece plugged into the end of the track. I haven't tried to remove or open it, but I believe it contains the connections to the cable in the wall behind it.

Since the bulbs are 120V I assume there are minimal/no electronics in the connection.

How about posting a picture? That piece sounds like an end connection I have, and if so, yes it contains the connections to the cable. Turn off the power and if it's like mine, there should be a plastic cover held on with one small phillips head screw. Removing that would expose the connections. Turn the power back on and measure the voltage between each pair of wires (Black to White should be 120, Black to Green should also be 120, White to Green should be about 0).

Thanks for the pointers. Yes, I think you would describe it as an end connection.

I will do as you suggest. But its a hassle to get to so I might not get to it right away.