How fast can she go? Why, I've had her up to 55 myself.
4 seconds sound clip from the Back to the Future Part III movie soundboard.
You can hear this line at 00:40:44.989 in the DVD version of the movie.
Quote context
[...]
- Monday! It's three days away!
- All right, all right, all right. Just let's think this thing through logically.
(STEAM TRAIN PASSING IN THE DISTANCE)
- How fast can she go? Why, I've had her up to 55 myself.
- I heard that Fearless Frank Fargo got one of these up to near 70 out past Verde Junction.
- Do you think it's possible to get it up to 90?
- 90? Tarnation, son, who'd ever need to be in such a hurry?
- Oh, it's just a little bet he and I have, that's all.
- Theoretically speaking, could it be done?
[...]