I suppose this idea has been done to death, but I didn't believe it until I tried it. After reading posts about nailed track being a problem with expansion and contraction I decided to test glue a section of flextrac before I went ahead on the real layout.
It works!...I bent a flex track into a 15 in radius and glued it down to cork roadbed, holding it with push pins for about 12 hours. It's on there firmly alright.
That's great, as I have a new section of elevated track on foam risers that I couldn't nail down anyway.....and some of it is in a 24 " curve.
However, I don't like the sheen of the dried transparent caulk....as I havent ballasted yet. so I Think I will create a "gluing area" of a strip of glue spread out and set the track down in it to get glue just on the bottom of the ties....then set it on the roadbed. I suppose the curved sections will smear it around on the roadbed anyway a bit, but the straight sections will have no overlap.
I think its a good idea to dip, so too speak, then put in place. A solution is to make sure you get the paintable type so when you paint ties the overspray will color the roadbed and caulk.
One note from my experience is that to use a very thin layer of caulking. You really don't need much. On the first couple sections I allowed too much caulking and it oosed up between the ties a bit. Once it dries its a bear to remove from between so many ties.
John
Maybe the real trick is to use colored caulk.
I've been doing my visible caulking (flex to roadbed, wood ties to roadbed) with grey caulk, which will hide the white cardstock templates and pink foam if I miss a few spots with ballast later. The shiny transparent (and gloss white) caulk goes between the foam and the plywood subgrade.
Chuck (modeling Central Japan in September, 1964)