They also chose to use the closed cell foam and carpet adhesive, and have come to reason that the sound deadening qualities are almost nil. Mind you I did think he mentioned express speed with eight on !
So now I am all a dither as to what underlay ( if any ) to chose, as I am at the stage of no return.
Decisions, decisions.........
.
Martyn.
Hi Martyn,
I was very saddened to hear of the track damage caused by heat expansion on the SR7mm Group layout, and, interested to hear their thoughts on what they felt to be a lack of sound deadening effect offered by the use of closed cell foam.
As you know, I also use this foam, and I have to say that in my case, the presence of the foam between sleepers and base-board, has certainly helped to decrease the 'base-board drumming' effect that I used to get when the track was laid directly onto the boards. As discussed earlier in this thread, I think it would also be interesting to experiment with taking this one step further, by adding an additional layer of foam between the base-boards and their supporting framework, in an effort to reduce any remaining 'drumming' even more.
My ideal, is to end up with rail hum and rail joint noise only, as since I use DCC sound, I don't want it to have to compete with base-board drumming. This is because I am keen to reduce the sound volume on all my locos, in an effort to maximise the sense of distance and speed, created by the sound increasing and fading as a train passes.
Anyway, here is a poor quality video of my test-track layout before I dismantled it in order to start work on my new layout. It's about 2 years old, and I took it when I was experimenting with designing my own DCC sound projects, and I wanted to hear how they sounded on video. However, it also illustrates the general lack of drumming noise coming from the stock as they pass the camera, and I hope this will give you an idea of what the use of foam might achieve. (apologies for the awful scenic state of the layout
!!!)
One further thought on the use of foam. I have read on several occasions, that if the barrier between baseboard and track created by the foam is bridged, then the sound deadening properties of the foam will significantly be reduced. Examples of this would be: the use of track pins and/or screws to fasten the track through the foam and into the base-board; the use of PVA to attach ballast, particularly where the ballast is also in direct contact with both the base-board and sleepers.
Hope the above is helpful
Mike
Ps: After listening to the video again, I know that there is a bit (?) of a clatter as the stock passes, but you should have heard it before the foam was laid
!!
. 
