I was told the course is much harder than any university course and it will be the hardest thing you ever do. This came from a current train driver who also has a uni degree.It's not harder than a uni degree, just very intense. You learn a lot very quickly. Very few elements of the course are difficult on their lonesome. Unlike University, you don't need to be an analytical or critical thinker, raw intelligence and dedication is enough to get you through.
The key to it is to study, study, and then study some more. Reading and re-reading is useless. Make your own notes, draw, acronyms... On average a class will lose one member, so 11/12ths of those who start become drivers...