Liked the movie. What made it feel dated was its slight under-plotting. The taking of the train itself was really all the twists we get. It really must have been that novel. Also, the fact that Matthau leaves the office ONCE, exclusively to skulk down to the underground, gun drawn, and murder the bad guy was... Dumb and blunt. It seemed like a studio note, like: "the big star has gotta kill the bad guy at the end. Get him down there!"