Or, it just "seemed" to be one small section...
Perhaps when weight was applied to that one small section, it was just enough to break contact for a nearby rail joiner... just enough to make the whole piece go dead... but use your hand to move the loco a few inches, and the weight on the rails shifted just enough to re-connect the joiner, which would make it appear as though there was a dead spot.
That's why a multimeter would have been useful. When the "spot" was dead, was teh whole rail really dead, but then the whole thing came back to life once the weight on the rail shifted again.
Putting in a new piece of track may have fixed an issue that was just a rail joiner all along.