attaching directly to hollow core door

[h2w]

compared to gluing the track down on a foam on top hollow core door or gluing the track directly to the hollow core door what would be noiser, vibration sounds etc
thank you
 mark

[johnb]

The foam will quiet the trains down

[lajmdlr]

The foam will quiet the trains down

But foam still acts like a sound board so you will hear the trains running. It may not be that noisy if the train speed is kept under 10 MPH as on a switching layout. But if the layout is mainline running the train noise will be worse.  Cork sheets or roadbed can be used to keep the noise down. Is homasote made thinner than 1/2"?