The clip Back to the future Part 2 from Back to the Future Part III (1990) with Christopher Lloyd, Bill McKinney
Is this a holdup?
It's a science experiment.
Stop the train just before you hit the switch track up ahead.
Uncouple the cars from the tender!
I've wanted to do that all my life.
What are these things?
My version of Presto Logs. Compressed wood with anthracite dust...
chemically treated to burn hotter and longer.
I use them so I don't have to stoke my forge.
These three will ignite sequentially...
make the fire hotter, kick up the boiler pressure...
and make the train go faster.