By far the most important part of the role is route knowledge and I can't say I know a route 100% comfortably until I have been driving it for at least a year. Getting the job in the first place is the most difficult part. Here is a list below for you to consider.
1. The training is very intense and unless you are good at grasping things you will find it very difficult
2. The shifts are quite demanding and it takes a while to get used to the shift rotation.
3. Retention of knowledge especially route knowledge isn't easy for some people.
4. Maintaining concentration is difficult at times when your mind is on other things.
5. The handling of each train is different even within the same class, some have very sharp brakes where some have softer brakes, this needs to be considered and as a driver you get the feel of a unit after your brake test and first stop.
6. A train driver needs to be conscientious and aware of their surroundings and prevailing conditions and to act on these, it's like a 6th sense.
7. A train driver will always be thinking ahead for instance, if you are following another service it is good to know the stopping pattern of the train in front so as to regulate your speed so not to encounter red signals.
There are many other parameters within the role but yes, it's a doddle