Most of my steam engine stuff is kept inside a glass curio so I get minimal dust tissues but I also dabble in O. scale model trains in the basement and the situation down there I use a small Industrial vacuum shop vac with a bristle brush and that tends to pull off any heavy dust on things without damage fragile parts!!!
Sounds exactly like my collection upstairs but down in the basement I consider the dust to be just "weathering" on my HO, O scale 2 rail and G gauge live steam layouts - saves me a lot of work but I do occasionally break out the kitchen basting brush if it starts to really get heavy.