Garage door rails are thickly rusted where they meet the floor

I have heavily rusted garage door rails especially where they meet the concrete slab. The garage door seal has been replaced and upgraded. I attempted sanding the inner track with a Dremel-ineffective. Attempted sanding with a cone shaped sanding electric drill bit-ineffective. Tried a product called Prematex Rust Treatment-was told the rust would "dripoff immediately"-I saw nothing. At this time, its necessary to attempt DIY home repair rather than hire a contractor and replace them. I would appreciate any and all responses, thank you