I was invited to a video interview shortly after the application. A panel of two senior members of the team conducted a competency-based interview, around the key behaviours highlighted in the Network Rail vision. There were also strenght based questions, in which a generic response was required (instead of an example) and a technical experience series of questions, which only asked for examples where the candidate had used a specific technique. There was also a security question.
The panel members were very friendly and approachable and the overall process was stress-free, although I did not get the job as I had "different" math background. Anyway, I appreciated the manager called me to persoanlly inform of the outcome instead of sending out a standard email.