Hello Dave (smiling as I recall 2001 A Space Odyssey, and a certain Apple Macintosh commercial).
https://www.youtube.com/watch?v=nHJkAYdT7qo
I was just looking at my notes this morning, so your question is perfectly timed!
1. When researching the idea initially, it was recommended that I use ArmaFlex Tap 18230 for the underlayment. It is available at Home Depot.
2. But then I found Mp Global Quietwalk Underlayment (100 square feet) at Amazon, which purported to have even better deadening qualities. Besides that, and because I live in the middle of nowhere, I wouldn't have to drive 75 miles to the nearest Home Depot. So, I bought that instead at $46 a roll. https://www.amazon.com/gp/prod...00?ie=UTF8&psc=1
3. Initially, I tried laying cut pieces under the track. But the stuff is a bugger to cut, even with a sharp knife. It is intended to be laid down in one piece. Nevertheless, the piece-by-piece placements resulted in measurable sound reduction! (my table top is 1/2 inch interior plywood).
4. Elsewhere on the table top I had glued down Woodland Scenic's grass mat. But I was not happy with that at all. Initially, I was thinking it would replicate the classic Lionel green on their marketing store displays sent out in the 1940s and 1950s. Not to be. It looked horribly fake and actually amplified noise.
5. So, I decided to lay the underlayment across the entirety of the table top. I stapled it into the plywood at about 12" repeats. The stuff lays nearly perfectly flat! The resulting deadening effect was even more profound! And remember those pieces of underlayment I'd cut earlier? I didn't throw them away. Instead, I used them to ensure a level track lay in various places. The picture will give you an idea.
Of note is the incredible dryness of a Laramie winter. My plywood table-top is measurably different now than it was back in, say, August. Dried out, I guess. The underlayment solves the problem of slightly uneven table-top, which is a good thing. But ...
6. This presents a slight problem with regard to scenery. The underlayment is squishy and would not hold even glued-down grass (I don't think). But I am not a modeler in that sense, so the problem is not that big for me. Still, as I intended to have lots of buildings and streets, I knew that the underlayment would be covered to some extent. For the remaining exposed areas I have decided to cover the underlayment with 1/2" poplar pieces cut to size.
7. I am in the middle of cutting those poplar pieces now. I have attached some pictures so that you get the general idea. As I do this, I am envisioning using the poplar pieces as one might use foam insulation board - that is, I will cut them to resemble, say, "stylized" buttes as one might see in the desert. Again, I am in this for the action, Dave, and not the scenery (although I admire greatly men who can model scenery with the incredible detail and realism that they do!).
8. I am thinking that once my layout is in place, a spray of sound deadening foam underneath the table top will also help. I will test that one section at a time (the bench work is from Mianne and results in neat and tidy 2' x 2' cells that would be perfect for limiting spray).
There you have it. Thanks for asking and thank you for your signature line about "walking in the way of the Lord." I have begun to use that line in my counseling of Christian and Jewish clients. It truly resonates with them, and me.
Dr. Joe
