Is MR 16 the track head type? So I should look for MR16 track heads, which will fit Solux tracks?
Correct. Kind of a '
universal' fit. So IF (and if they are like mine) you have Solux bulbs for MR 16, and you find an MR 16 track, they just pop in.
You may end up needing a new track but again, if MR 16, and there are hundreds, just replace and use those bulbs.