We come from Fond du Lac, about 14 miles out, so the truck is stocked before we leave rather than restocked on site. For an off-track call on a Campbellsport-era door, that means carrying track sections in a couple of widths, since narrower rail from this vintage doesn't always match what's common on newer builds elsewhere in the service area.
We also carry replacement rollers, bottom brackets, and lag hardware, because a door that's jumped track usually took a bracket or a roller stem with it. If the track itself is bent rather than just knocked loose, we carry enough straight stock to swap the damaged section rather than trying to hammer a 1950s-gauge rail back true, which almost never holds.
One honest limit here: if the track is a discontinued profile that nobody stocks anymore and the section needed is longer than what's on the truck, we may need to order it, and that's a return trip rather than a same-visit fix. It doesn't happen on most calls, but on the oldest doors in this area it's a real possibility worth knowing about before we're on site.