My car was towed under warranty to the dealership by Saab. When I got it back it was completely covered in orange dust. After several washings, the "dust" is completely embedded in the paint. The whole car looks speckled and feels like sandpaper. The little pimples under the paint look like rust. I can still see the orange dust in the gap between the seals and the windows. The windshield is even speckled and looks like it has a dirty snow film on it. I had purchased the 2006 Saab from carmax about 6 months ago and haven't seen any problems with it prior to this. The service guy at the Saab dealership says it must have gotten rail dust on it during the tow. Saab corporate won't return my calls. I'm now bumping it up from calling once daily to 3 times daily. We'll see. Anyhow, can this be rail dust? Can you get it from being towed? Does claying fix this or just temporarily hide it? Is there any hope of Saab helping me with this since they arranged the tow under their warranty?

That sounds like spray paint 'overspray'. If someone is painting a car or spraying primer without proper ventilation, the paint spray particles will go all over the building and settle on everything, including your car.

Modern paints 'dry' very slowly, so paint droplets floating in the air will still be 'wet' and can still stick to things for many minutes after floating in the air. So your car could be far away from the source of the paint but still get covered.

Occasionally this happens outside. I have heard of people spray-painting buildings, ships, bridges etc on windy days and everything downwind for hundreds of yards still gets covered. You might want to visit the dealership again and look around inside or out to see if you can see any source of contamination.

BTW..... rail dust?? Are you near a train yard? Orange paint is used rarely, except as a metal primer, and also to paint railcars..........

I suggest to call your insurance company and report this. Take the car to a couple of body shops and/or detail shops and get their opinion on what has happened. Ask for estimates on repair. Chances are the substance can be removed without repainting your car but it will take some work.
Send the estimates to the dealership. Make it clear you are holding them responsible for the repair expense. Contact a lawyer if they are not cooperative.

If you had a pre-existing condition of rail dust, it could be some neglect might have made any wax disappear and the rail dust bloom -- though that's just a real big stab in the dark.

If it was the tow, it could have been particles from the tow vehicle's brakes or some source of metal flakes.

Or some mechanical work being done nearby while at the dealer that could have caused metal flakes to disperse onto the vehicle.

I'd try using a clay bar and a polish -- $20 or so from your local auto supply, and if that didn't work, I'd have it inspected by a competent detailer, but your first point of contact would likely be the dealer where it was just at.