I heave read about using Homasote on top of the plywood table, but Homasote is not available within 30 miles of where I live (I’ve checked extensively). Can I use MDF (medium density fibreboard) instead of Homasote?
No, it is too hard.
You did not indicate where you live. Homosote is pressed paperboard and may be sold under a different trade name in your area, e.g. upsonboard or insulation board.
The advantage of homosote over other types of roadbed materials is it’s death grip on spikes. Unless you intend to handlay or nail your track in place, the choice of roadbed is dictated by how much sound deadening you desire. Any hard material, like MDF, will act as an amplifier to the sounds of the trains. However, many soft roadbeds lose their sound deadening qualities when they are coated with a hard shell of ballast.
I used MDF instead of plywood, then used a homasote type board over the top ( we call it pinex or flameguard ).
Mdf is prone to expansion in high humidity areas.
Ken.
MDF is also tough on saw blades. MDF is best suited for constructing furniture, not for benchwork.
Look for a product called sound board or Upson board – it is a brown fiber material that is not as hard as homosote and is much easier to cut, glue, cut into, paint, whatever. We used two 1/2-inch thick layers of it on our club layout glued in place with caulking; glued cork roadbed to it, and used sewing pins to hold the track in place. After ballasting, the pins were either removed or the tops were colored black with a permanent marker.