Marty: So what'll we do?
Cut to the area outside Hill Valley. The DeLorean is being pulled by horses. Doc and Marty sit on the roof. Doc has a whip in his hand. Marty is reading the speed off of Doc's digital speedometer.
Marty: Uh! Uh! Uh! Uh!
Doc: Ya! Ya!
Marty: (re: speed) 24!
Doc: It's no use Marty! Even the fastest horse in the world can't run more than 35 or 40 miles an hour. (to horses) Ya! Ya! Ya!
Cut back to Doc's shop. Doc is pouring some liquid into the DeLorean and Marty is inside it.
Marty: (re: liquid) Bartender says that's the strongest stuff they got.
Doc: Try it, Marty.
Marty tries to start the car, but it stalls. There is a strange noise coming from the back of the car.
Doc: Need more gas...
BOOM! The fuel injection manifold breaks off the back of the DeLorean.
Doc: Damn! It blew the fuel injection manifold. Strong stuff all right. It'll take me a month to rebuild it.
Marty: A month? Doc, you're gonna get shot on Monday!
Doc moves to a window. Outside we can see the railway station. Next to the window is a calendar with the date - September 4th 1885 - on it. Doc turns around to face Marty again.
Doc: I know, I know, I know! I wish..... wait, I've got it! We can roll it down a steep hill..... no, we'd never find a smooth enough surface. Unless..... of course..... ice! We can wait until winter when the lake freezes over...
Marty: Winter! Doc! Monday! It's three days away!
Doc: Wait. Let's just think this thing through logically. We know it can't run on its own power, and we know we can't pull it. But, if we can figure out a way to push it up to 88 miles per hour... huh?
Outside, we can hear a train whistle. A steam engine pulls into the station. Doc looks outside and spots it.
Doc: That's it!
Cut to the station. Doc and Marty are talking to the train engineer.
Engineer: How fast she can go? Why, I've powered her up to 55 myself. I hear that fearless Frank Fargo got one of these up to near 70 out past Verde Junction.
Marty: Is it possible to get it up to 90?
The engineer laughs.
Engineer: 90? Tarnations, son, why'd ya ever be in such a hurry?
Doc: (covering) Well, it's just a little bet that he and I have, that's all. Theoretically speaking, could it be done?
Engineer: Well, I suppose if you had a straight stretch of track with a long level grade, and you weren't hauling no cars behind you - and if you could get the fire hot enough, I mean hotter than the blazes of hell and tarnations - well yes, you might be able get her up that fast.
Doc: When's the next train coming through here?
Engineer: Monday morning at 8 o'clock.
Cut to the waiting area. Doc and Marty are looking at a map of Hill Valley. The clock for the clocktower is on the platform - it's just been delivered. And the time on it is 10.04am! CLARA CLAYTON can also be seen waiting for someone to pick her up, although neither Doc nor Marty see her. As Doc describes the places, he shows Marty on the map.
Doc: Here. This spur runs off the main line 3 miles down to Clayton Ravine. There's a long stretch of track that will still exist in 1985. This is where we'll push the DeLorean with the locomotive. Funny, this map calls Clayton Ravine Shonash Ravine. Must be an old Indian name for it. It's perfect. Nice long run that goes clear across the bridge over the ravine, you know, over near that Hilldale housing development.
Marty: Right, Doc, but according to this map... there is no bridge.
And as we cut to the Ravine, we see Marty is right. There is a dead end for the tracks, and a sign saying the bridge is scheduled for completion in 1887.
Marty: Well, Doc, we can scratch that idea. I mean, we can't wait around a year and a half for this thing to get finished.
Doc: Marty...it's perfect! You're just not thinking fourth dimensionally!
Marty: Right, right. I have a real problem with that.
Doc: Don't you see? The bridge will exist in 1985. It's safe and still in use. Therefore, as long as we get the DeLorean up to 88 miles per hour before we hit the edge of the ravine, we'll instantaneously arrive at a point in time where the bridge is completed. We'll have track under us, and coast safely across the ravine!
Marty: What about the locomotive?
Doc grins.
Doc: It'll be a spectacular wreck. Too bad no one will be around to see it.
Clara: (o.s) Argh! Help me!
Doc turns to where the sound is to see a woman, Clara Clayton (who was at the station earlier) in the distance riding on a buckboard with out of control horses. They are heading for the edge of Shonash Ravine.
Doc: Great Scott! (to horses) Git!
Marty: (to his horse) Hiyah!
Doc catches up to Clara and manages to shout to her.
Doc: Jump!
She jumps off into Doc's arms just in time. The horses veer left at the end of the ravine, the wagon breaks off and falls down the ravine.
Doc: (to his own horse) Whoa.
Clara's hat sits on her head and covers her face.