He said are there any technical questions at the interview. My personal experience says they will deffinatly ask you some type of technical questions. One of my interviews was things like what electrical components would I find in under a car bonnet, and what is a ring main and how does a compressor work etc. That was my first job for working on trains so for my second job interview (I left the previous job) they asked me more train orientated questions such as the interviewer pulling out a relay and asking what it is, how it works and to list components inside of it, and all the rest were tell me a time when.......blah blah blah. On both my interviews i got asked things like what is a torque wrench and how to use it and what effects it could/would have if not used correctly.
As said before, when answering questions always keep safety at and risk as number one priority.