You are nistaken my friend. There are a lot of positions where adegree is either required or preferred, but equally there ar emany where it has no relevance at all.
The simple fact is that, due to the economic situation, there ar emore graduates applying for jobs which they would nt have touched with a barge pole a few years ago. The fact that some of these graduates are successful with their applications does not necessarily mean that they have been appointed simply because of their degree.
Train driving in particular requires a particular type of person with very specific skills and abilities. If someone has those, it will not matter too much if they have a degree or not.