This sounds to me like the axle gear on the drive unit may be cracked. There are many accounts of new, in the box, older or vintage trains having a cracked gear even though it has never been out of its box. I believe that the older plastic gear becomes somewhat weak and with the first runnings may crack with the torque. Here is a way to find out if this is indeed the problem, turn over the drive coach, is it Annie, turn on the motor, gently apply some pressure on a drive wheel with your thumb, if you can stop the wheels from turning but still see the gear moving inside, its the drive gear that is cracked.
Are you using a phone or computer for uploading a video?
Are you using a phone or computer for uploading a video?