Marty, the new gauge on the dashboard will tell us the boiler temperature.

4 seconds sound clip from the Back to the Future Part III movie soundboard.

You can hear this line at 01:35:35.614 in the DVD version of the movie.

Quote context

[...]

- These three in the furnace will ignite sequentially, make the fire burn hotter, kick up the boiler pressure, and make the train go faster.

- Ready to roll!

- Marty, are the time circuits on?

- Check, Doc!

- Input the destination time. October 27, 1985, 11:00 a.m.

- Check.

- Okay, we're cruising at a steady 25 miles an hour, Doc.

- I'm throwing in the Pres-to-Logs.

- Marty, the new gauge on the dashboard will tell us the boiler temperature.

- It's color-coded to indicate when each log will fire. Green, yellow and red.

- Each detonation will be accompanied by a sudden burst of acceleration.

- Hopefully, we'll hit 88 miles per hour before the needle gets much past 2000.

- Why? What happens after it hits 2000?

- The whole boiler explodes!

- Perfect!

[...]