I have latterly being laying it "spot fixing" it with epoxy, the five minute stuff you can buy in sensibly sized bottles from Eileen's et al.
I do this in order to set up correct (hopefully) alignment, level and "top" of the rails, lots of examples of how this doesn't always work back up the thread.
What is really fixing the track though is not the epoxy, but the Ballast that I then add. This is put on dry, shaped, wetted and then flooded with SBR.
I cannot recommend this method highly enough, it makes for a phenomenally robust and permanent formation and looks great, it also helps keeping the track clean as detritus can't get stuck between the sleepers.
Simon