From your description, there's not much to go on other than you took the right approach to tracking it down. Evidently, moving wires and track was enough to undo the problem.
It could have been a loose connection that developed over time. Or it could have been some sort of electrical debris on the tracks that became dislodged by your efforts to locate the problem.
Anyway, sometimes luck is the best medicine. Just keep an eye on that green light for further developments.
