Any thoughts on using the M track 7171 soundabsorbers. Could one use strips of thin foam rubber or soft rubber sheeting instead. IF using 7171 do you have to use 2 per rail?

To minimise sound from the track it's also a good idea to minimise the number of screws used to hold the track in place. The sound travels through the screws into the wood of the baseboard which then amplifies it. On my old M track layout I got a significant reduction in noise by only having one screw for every 3 pieces of track instead of 2 screws per track as I had previously