Thanks everybody,  I am introducing model railroading to a group of 3-10 year olds so I was naturally looking for something with limited vocabulary and no reading yet.  Kind of a visual (very little narrative) show and tell or just show.

Hello, does anyone know of a good, free downloagable video that would introduce a young first time user of HO trains about the basics such as:
how to couple/uncouple
putting cars on the track
basic wiring
basic troubleshooting

Thanks for any leads.