There’s a moment near the end of Back to the Future Part III where everything that made the trilogy work gets pushed into one sequence. A train is barreling forward, a time machine is barely holding together, and three different eras collide in real time. I saw it in the theater in 1990. My mother still looks back and talks about how tightly she gripped the armrests as we watched the scene unfold for the first time. Even with over five hours of the trilogy behind it, the sta