In the past i've always nailed track down with little pins, this goes back to my old OO days which is simply how it was done (apparently). Nailing track down is a lot harder with N gauge though not impossible. The issue is always getting the track back up at a later stage without damaging it, which quite frankly i suck at.
With New Knell Lane i'm trying something different. I'm using PVA glue to fix the track down. A trial a few weeks ago seemed to work pretty well so hopefully this will work on the new layout. But if it doesn't work and i'll can just go back to nailing it down... but fingers crossed.