Hello James. Either the camera following a curve or the camera rig will do just fine. What you mean is that moving the camera around and keyframing it is a pain Lol. Happens to me all the time, moving the camera is super tricky and if you’re not careful it’ll start making moves that you don’t want it to. Have you watch Wayne’s camera course:
https://cgcookie.com/courses/directing-the-camera-in-blender
There might be something in there that can help. All I can say is to keep trying, I learned to control the camera little by little, failing over and over again until something click and I was able to control it better and better. The aim lock can be tricky to master, but it’s helpful once you get the hang of it to get the precise shot you want.

What I do is I try to take it one step at a time. First start broad, the major camera move, maybe starting with the passenger and then the following of the train in your case, broad moves, nothing fancy yet. Then once I feel I nailed that, I refine it, the rotation twists and turns, then the aiming or lock to a specific subject. Each time going up in complexity and if I feel I screw up and the camera is jittering or going haywire, I step back to try and refine that step before going to the next.