Final answer:
The Great Train Robbery introduced several innovations to action films, including using trains as a motif, employing cross-cutting techniques for tension, and featuring complex storytelling.
Step-by-step explanation:
The Great Train Robbery, directed by Edwin S. Porter in 1903, introduced several innovations to action films. Firstly, it was one of the earliest films featuring trains, which would later become a popular motif in action and Western films. Secondly, the film utilized cross-cutting techniques to create tension and suspense, a technique that would become a staple in action films. Lastly, The Great Train Robbery featured a narrative structure with multiple locations and characters, setting a precedent for complex storytelling in action films.