Started with a "work demo" which wasn't difficult but I have never seen somthing like that before. Second I did a group work demo with 3 other candidates. Lastly was the more traditional interview there were 7 people and it was very straightforward with their questions.

Pre employment test included math, reading, mechanical reasoning, gauge reading and gauge reading. Marathon test included a VERBAL retention exercise. Person spoke from podium. Tested on what you remembered. Another aspect of the test was a pipe following exercise which tested depth perception. E.g. which pipe covers which pipe.