I need to know the title of this movie, this is what I remember about it

2 kids visit this old guy who is repairing/ fixing this antique car, the parents of the kid say not to go to his place, later in the movie the old guy gets the car going and he takes the kids for a ride in it around the paddock. Near the end of the movie the old guy go's to this house to get something from it, they have a muscle car with a supercharger sitting in the driveway, then he gets on a freight train and the movie ends