One of the trickiest problems with digital photography in general and cellphone photography in specific is the concept of zoom. This is complicated for beginning photographers by the fact that it’s not clear how much “Zooming” is actually taking place on a camera from spec sheets unless you know how to read them correctly. There are two kinds of zoom that are generally spoken about with digital cameras. Optical zoom and digital zoom.
Optical zoom involves physically moving lens elements so that the magnification of the image that falls on the digital sensor physically changes.
Digital zoom on the other hand involves resampling the size if the final image that is taken, effectively losing resolution. While various cameras will claim 5x, 10x, or even 100x digital zoom, these numbers are all arbitrary as an image can be zoomed in this way in photoshop or any other imaging program to any level at a later time with the same loss of resolution. In fact, sometimes the results might even be better with Photoshop than they would by doing it in camera.
Very few cellphone cameras have optical zoom, due mostly to the small form factor of their camera forcing the lens to be fixed. Therefore it becomes of tantamount importance to actually compose the shot properly by moving your vantage point or the position of the subject.
For photos of like this one, where I was trying to capture a subject I had no control over, the trick is patience. Before the train ever arrived I planned my shot. I knew where I wanted the train and I framed the shot ahead of time, focusing on the tracks where the train would be. Then I steadied myself and waited for the train to arrive. You want to get as much preparation done ahead of time as possible since there’s no second chances. If you miss the shot, you’d simply have to wait for the next train to come through.
I find that the best solution is to stand a little further back than you anticipate needing to, so as to have some extra space to play with and then crop the image to be correct afterwards. After this the image can be processed in photoshop as normal, in this case this involved some subtle sharpening and color processing to bring out the blue in the sky.