Unhelpfully, there's no picture in the manual, just the words.
Even if the tracks are in a stillage, is there still a chance of counting the links? It seems logical that if there's the full 90 per side or close to it, the tracks can't be that worn. If there's only, say, 87, you know they must be pretty far gone as the other links will have been removed to achieve the correct tension. Just a slightly lateral thinking way of addressing the issue.
Andy