There could be many reasons for rejecting. As someone who reads applications every day, though not for any railway organisation, I can say that there are definitely people who would probably be an excellent candidate who fail because their application form is poorly worded, lacking in relevant information, or beset by spelling and grammar errors.
What the recruiter for any position is looking for is a close match between the information laid out in the application and the specification for the person and job as set out in the advert. Not only that, but it is far better to set out situations you may have faced, how you dealt with the situation and what the outcome was. This tells someone far more than something like 'I have a great deal of knowledge of xxxx'.
You may not believe how quickly you tire of reading the same thing over and over again, usually something like 'I am a hard working, conscientious individual who has a lot of experience in dealing with people'!
