Hi,
To clean dust off of the trains I built a box with a vacuum that blows air down in the box and 2 vacuums on both sides of the center suck the dust out of the box. This way the dust does not escape the box except in the vacuums. I just run whole trains through while the vacuums are running.
Below is a link that I hope works to show it in action. The train goes into the box with the dust on the cars and comes back to the starting point with the dust blown off and sucked away. Be sure to observe the dirt and dust on the flat car and gon before it goes into the box.
