Well the upside down trick did not alter the outcome. The screw turns in to a full stop, it turns out to a full stop but turning it in does not result in a firm connection. The wire "floats" in the pocket. Attempting to operate the loco in this condition results in intermittent loss of power. I thought perhaps the wire was too thin and folded it back on itself, still fits in the pocket, pushes all the way in but turning the screw still provides the same result. I wonder if there is anything that can be placed on the wire that will expand in the pocket providing a better fit?