This picture shows that only 3inches (75mm) of fine blue stone chips are
used as ballast, I lay the track where I want it to go... scoop out 3inches
of whatever is underneath and fill up on top of the track with the ballast
then pull the track up through it... well its the way we did it also on the
Otago Central line, and it works out great in 'G' guage too .. assuming that
you have 60ft of conglomerate under it! Best thing is the track stays put..
it does not move once the ballast is round it.
Anyone who would like a sample of this ballast let me know and I will
forward them a sample (sample not truck load!)