A reasonable summary, although one thing in particular stands out for me
If you want much of the photo to be in acceptable focus, then never set your focus point on the front of the train, especially if you want to maximize depth of field (e.g. f stop 11 or lower. You may find much of the rear of the train to be so out of focus, it could be distracting. As a rule of thumb, I estimate what is called the "hyperfocal" distance about 1/3rd into the frame and this is where I set my focus point. Any further back and the front of the picture (or the engine, depending where it is in the frame) and the front will be out of focus.
With regard to shutter speed, it depends on how fast the train is moving and whether it is moving from left to right (or vice versa) or towards you. If it is travelling towards you at a speed of over 60-70mph; I would not use a shutter speed lower than 1/1600. If it is travelling directly across the frame, then 1/2000 minimum.
As a rule of thumb, for express electric or diesel trains running 80mph+, I would shoot at least 1/2000. For a steam train, capturing it may be your one and only chance so setting the right focus and shutter speed is crucial. If you fluff it up, no amount of post processing will correct it.
And remember to set your ISO appropriately