The railway environment is full of vertical rectangular shapes which can sometimes take on an unexpected 'leaning' appearance in photographs.
Below you can see an example picture before and after correction. The photo shows Irish Rail 233 entering Claremorris station on 1st June 2006. Note how the semaphore signal and pole on the left of the picture are leaning to the right. This article explains what causes the effect and how to correct it after a picture is taken.