Just to follow up, Bachmann customer support recommended I try a 9v battery across the wheels to test the locomotive itself, separately from the track layout, etc. That also produced no light or movement. I started gearing up for a warranty request.
While doing that, I clicked into the parts list and looked around a bit. I noticed that the copper contacts part looked slightly different from what I had seen when I took a few screws out to see if there was anything obviously jamming the mechanism. One of the two tabs that reaches up into the body of the loco to transfer power to the motor/light had been installed incorrectly, and was not sitting where it should have been. A little adjustment brought the small flap up, and after reassembly, the train began moving correctly.
So, for any other newbies who run into a totally nonfunctional locomotive: try a 9v battery, and check that the copper bits that are supposed to move power around look right.
While doing that, I clicked into the parts list and looked around a bit. I noticed that the copper contacts part looked slightly different from what I had seen when I took a few screws out to see if there was anything obviously jamming the mechanism. One of the two tabs that reaches up into the body of the loco to transfer power to the motor/light had been installed incorrectly, and was not sitting where it should have been. A little adjustment brought the small flap up, and after reassembly, the train began moving correctly.
So, for any other newbies who run into a totally nonfunctional locomotive: try a 9v battery, and check that the copper bits that are supposed to move power around look right.