Are there any other advantages than to reduce noise in laying track mat
Assuming you mean roadbed and not mats, the beveled edge looks more like real track after it is ballasted.
If you’re referring to sheet cork mats, one of the main uses for them is to have a flat yard meet the cork roadbed at the same height without having to do tapering or a lot of sanding etc.
Does not cork not dry up and crumble ?
I know there are some here on MR that have repeatidly said that cork dries up and crumbles, but I’ve been using cork for over 30 years and it’s never dried up and crumbled on me. I even have a few tracks that still haven’t been ballasted for more than 5 years and the cork is not dried out. It kind of depends on the environment and whether you ballast or paint it (effectively sealing it).
It may be that in recent years (or decades) cork has been made or treated with something so it doesn’t dry up and crumble. I know the cork I used in the early seventies got very brittle in time…part of the reason I haven’t used it since. There are alternatives, like “RibbonRail” which is made from Upsom board and comes pre-cut in various radius curves along with straight pieces.
I have never personally experienced the brittleness of aged cork roadbed, other than noticing that if I try to pull up old roadbed that has been in place for years it is more likely to break than new stuff. But not many of us try to reuse roadbed particularly once ballast is applied. Back in the 1960s Atlas had the idea of introducing a rubber based roadbed (somewhat like the undermats for carpeting) and when I salvaged my old teenage layout from my mom’s house, I found that yes that rubber (one piece, unlike cork) roadbed did become exceptionally brittle and crumbly over time. If I had secured my track with ballast however perhaps that would not have made any difference.
Other reasons to use it? Cork roadbed helps to unify the surface below the ties so that very minor variants and changes in surface do not translate directly to the track. Obviously there are practical limits to what can be masked at the track level, but slight variances get smoothed out by the cork.
And cork (or any other material) roadbed realistically replicates the slightly raised track profile of the prototype. Since most of us build our layouts on flat surfaces, the raised roadbed gives us a bit of elevation so that we can model culverts and slightly undulating ground around the track as well. In fact I elevate the track area with 5/8" plywood or 1/2" Homasote sub-roadbed, with the cork roadbed above that. That gives me several scale feet of elevation above the flat surface, meaning only things like rivers, creeks, and gravel pits need to be cut into the plywood surface itself yet the elevation of buildings and streets can vary quite a bit, helping to avoid the “earth is flat” look. It also makes it more practical to have sidings at a slightly lower elevation than the main.
Dave Nelson
Depends on what type of track you want to model…
On my Industrial switching layouts I want the look of urban industrial branch line track and that calls for no or very little roadbed so,I use Woodland Scenics 12" x 24" “super sheets” for my roadbed and glue the track directly to the sheet…I then l lightly ballast the track using a mixture of dark gray ballast,grass and earth followed by small weeds between the rails.