The following is a link to the National Transport Commission, which is the information source for decision making about category assessment requirements.
https://www.ntc.gov.au/codes-and-guidelines/national-standard-health-assessment-rail-safety-workers 

Category 1

High Level Safety Critical Worker:

Includes 3 health questionnaires (re sleep, alcohol & mental health), clinical examination including audio, cardiac risk assessment, 12 hour fasting bloods and an ECG.

** Category 1 requires 12 hour fasting blood test – individuals must not eat or drink (other than water) in the 12 hours prior to their appointment.

Category 2

Safety Critical Worker:

Includes 3 health questionnaires (re sleep, alcohol & mental health), clinical examination including audio and cardiac risk assessment

Category 3

Around the track personnel in uncontrolled environment:

includes audio, eyesight, hearing and mobility.