Hi all, just wanted to post here in case I can help anyone in the future.
I have just recently passed my Network Rail signaller medical, whilst being diagnosed with Autism and being on SSRI's for that reason. I know a lot of people are probably worried about not passing the medical if they have similar circumstances, so I am happy to answer any questions or offer advice to people if need, either on this thread or privately.
I will be 100% honest that it wasn't the most straightforward process, and I do feel like the clinical team could use more up to date training on non-physical health issues, however it has all been resolved now so don't want anybody to not apply just because they don't think they will pass the medical for those reasons.
Obviously my experience is limited to NR, but happy to help as much as I can.