KATO GE C44-9W New engine, quick failure

[MrWobbly]

I purchased two of the KATO GE C44-9W engines some years ago when they were in short supply. About 8 months ago, I took them out of the boxes to run them. One of the engines ran about 48 feet and stopped running. The other has run continuously. Upon inspection, all connections look factory-fresh. I use lead wires from the transformer for testing. The good engine operates when wires are touched to the wheels. On the bad engine, touching the wheels only produces a spark. Also, the lights do not come on. The engines have Santa Fe Warbonnet colors.
QUESTION: Why would a new engine just malfunction so quickly? What should I be checking? Please advise. Thank you.