If you use compressed air to clean your trains you’re not getting rid of the dust, you’re just blowing it into a different place. I installed a built-in vacuum system when I built my house with two inlets in the area I was going to use as a train room. On reasonable intervals I use the vacuum system with a soft brush attachment to vacuum the trains. Then about once a year I use the old elbow grease method and carefully clean all of my trains. I have about 150 feet of shelves with trains coupler to coupler so it might take a day or a day and a half.
You can certainly use a portable vacuum to accomplish the same thing. It might even be easier.
Jim
I like your method, especially using an open window so as to not just redistribute the dust.
I have found that Electrolux has the softest bristles on its round dusting attachment.
Alan
Check the wind. Add a window fan
Unless really bad and you're careless/impatient, blowing a whole semi-clean room top first then down, is actually very effective too; if you allow enough "dead air" time for "fallout" to happen. Great if you keep up on room maintenance often, but aren't quite a full time "white glove" person.
The outside following us in can be a loosing battle at times. But most household dust is our old skin and hair. Pets, our kids, and the elderly mean more white/grey dust per pound
Light, fine dust looks a whole lot like industry fallout to my eye; so I like it until it gets too "fuzzy" or picks up a fingerprint. (Too fuzzy ...in the 50's Detroit's mill fallout might be 1/4"-3/8" deep in the morning ..but that's just too much yuck to "model with"
You needed a broom for the car more. mornings than not
Auto compose refuses to let me change many things here, so it's unedited; a "scattered" list of info/ ideas.