“Sound barrier” – I am not an acoustical engineer, but I believe
the effectiveness of the roadbed sound attenuation comes
from the mixed materials. Doubling the thickness of a cork
roadbed does not change the sound very much. Thicker
Homasote has little effect. But mixing layers makes a differ-
ence. Each material will tend to transmit a different spectrum
of sound waves. What vibrations get passed through cork
will be somewhat different than the spectrum transmitted by
camper tape. I suspect that in the cork/camper tape mix, the
cork provides some damping and the camper tape does a good
job of isolating the sound from the plywood.
Montanan:
I use a product called Homabed [2] and it is fairly
quiet, but you can still hear some noise. There will always be
some noise, I guess. I really don’t notice it. The only time I ever
noticed any noise is when I put a camcorder on a flat car and
ran it around the layout.
J. Graffi:
I went with a foam roadbed by Woodland Scenics and
glued the track down with diluted white glue. I did not drive
the locating nails tight with the ties and made sure there was
some give. I ran the trains without ballast for a year or so, and
was impressed that there was little if any noise. I could hear the
clackity-clack of the wheels going over rail junctions and turn-
outs everywhere on the layout, even with two trains running.
Recently, I began the ballasting process and hear no difference.
Rick:
On my previous layout I had a large (3’ high) plaster cloth
mountain, and when the train went through that area there
was a disturbing unnatural roaring sound. I cut the plaster cloth
where it attached to the plywood sub-roadbed and stuffed
foam rubber between the two, then used rubber cement to
glue down the ground foam onto the foam rubber. The roar
was gone.
Questions, Answers & Tips -
MRH-Nov 2014
