Never gave it a thought when I went to add mulch to my layout, I already had pine bark in some beds in the yard and didn’t have a problem. With a railroad there was just one itsy bitsy problem, THE DARN STUFF FLOATS. And when it does it will migrate and then settles wherever it happens to be when the water level recedes. To make a long story short, I got tired of having to clean track and switches everytime I watered so out it has gone replaced by a mulch that does not float.
I’m not sure what you mean. What kind of mulch doesn’t float? Teakwood? When I use the garden hose, I too get mulch on the tracks but when it rains I don’t b/c my roadbed is higher than the mulched areas. But the garden hose is kinda powerful and moves the mulch around. Eventually, I hope to replace all the mulch (or most) with groundcover and the bare spots with Preen.
I gave up on floating mulch a couple of years ago and on the advice of the local nursery developed an alternative. I mix spagnum moss with some dirt with high clay contact to make an adobe type mixture that I put down in those areas that are highly visible. Settled in nicely, looks like dried scale grass and it doesn’t mind being walked on. Really sucks up the water when the area is being watered.
I am now trying cypress mulch and so far so good - as I am just finishing an expansion I will not be able to get the landscaping this year so am using mulch to keep the weeds down. Hopefully next year plants can take over.