It sounds like a simple case of your connections still not connecting. Try re-tracing the wires and connectors from the controller to the track - with an ohm meter if possible. Or connect the controller to a spare piece of track & try your locos there one at a time. You can try touching the wires from the controller to the pickup wheels of your locos, one on each side.
The only other thing that crosses my mind is both your locos and controller defaulted back to #3. If you have changed numbers of your locos with your controller try running one at a time on #3. If no joy then try other numbers.
Can you get a spark by shorting across the rails? Or better yet, check for voltage on the screws of the controller and track?
What brand locos are they? (should make no difference)
Let the folks here know, someone may have 'been there & done that.'
G'Luck-
Rick