I've made 3 as a track worker.
1) 2006 IIRC
I witnessed a suicide. Watched someone jump and the train hit them. I'd only been on the railway a few years at that point. After letting the, er, 'debris' settle and running down the track to the nearest SPT (which was on the end of the station platform), I recall rattling off the emergency call script (I think fairly accurately) at very high speed and the signaller saying something like "ok, ok, calm down, the tracks are closed. Tell me what you can see."
He calmly slowed me down, stepped me through the information that was needed and confirmed some details with me and told me the emergency services were already on their way. I also clearly remember asking about the welfare of the train driver and asking if he wanted me to walk up to the train and check on them. He said that the driver had already made their emergency call, was fine, and one of the things the driver had said was that he was concerned about the welfare of the track workers that were close by, and the signaller would now relay back to the train driver that I was ok too. Nice to know we both did procedures then checked on each other!
The signaller then also coaxed out of me where I worked and the name and phone number of my boss, who he then phoned. My boss recalls receiving a very unusual call that morning to inform him that one of his staff members was ok but had been involved in witnessing a suicide and may need a bit of support.
I am very grateful to that signaller - they did a great job.
After that my team and I helped clear the station of the public and I met the paramedics who arrived first. One was in her first week on the job and this was her first suicide - I felt a bit sorry for her as the scene was really not nice. The fire and police then arrived and the MOM too, who took control.
I recall the BTP officer who interviewed me describing me as "gold dust" as it was rare to have a witness who was so close and could describe exactly what had happened and confirm there was no-one else around so it was indeed a definite suicide, especially a railway worker and not just a member of the public.
After declining counselling or help and when the tracks re-opened after a couple of hours, I went back to work and continued my survey.
Just after 5PM, I finished the work, said goodbye to my collegues, and got in my car to drive home. I made it about a mile up the road before I pulled into a petrol station and sat there and cried, as it all finally hit me. I got a coffee and some chocolate and let myslf calm down for a good 30 mins or something before I could carry on.
I met the persons family in coronors court some time later, where I had to descibe what I had seen and confirm it was definately their intention to take their own life. The persons mother came up to me afterwards and said thank you. I'll never forget that. She said it was horrible hearing me describe it all but also brought her some closure as she knows it was clearly their decision to do it and they didn't suffer.
2) Grand Junction, Birmingham, 2011ish IIRC.
I was working about here:
https://goo.gl/maps/d24Kqpi8xp5rG5Ub8
A man entered the railway somewhere to the East and I saw him walking towards me, very close to and then in the 4ft on the Down Main!
A train approached on the Down Main and the man got out the way in a very un-bothered manner. I saw the driver look at me and point towards the trespasser and I responded by waving my mobile phone that I was already dialling on and putting my thumb up to them.
I made an emergency phone call and remembered the script well. The signaller confirmed he was the right person and then confirmed with me exactly where the man was. He dropped a signal to red in front of a train leaving New Street, which stopped near me. After cautioning the train it continued along, and the next few trains were also stopped and cautioned and came through slowly.
The man dissapeared off into the arches on the North side of where I was working. BTP attended, met me and had a chat, then went to look for him. They found what looked like where he had been living, although they couldn't find the man himself.
I went back to work ok and felt fairly good with myself for staying calm and remembering the script and following the procedure.
3) Acton, GWML, 2016
I was in the Up Relief cess and a HST stopped on the Down Main opposite me, with what I later found to be a brake problem.
After the train had been stationary for about 5 minutes or so, someone on the side of the train I could see (so towards the adjacent tracks) opened a door and leaned out to see what was going on!
I phoned the signaller, checked I was talking to the right person, and described what was going on, following the script pretty well I think. One of my last lines was "I require you to stop trains on the Up Main past the stopped train .. oh s**t, a train" - A HeX came on the Up Main at fairly high speed. Cue horn sounding from the HeX driver and thankfully the fool on the HST closing the door just in time.
After that fright but nothing actually happening thankfully, the Up Main was indeed closed anyway for a time. The signaller phoned me back after a bit to ask what was going on and check there had been no further instances of the door being opened or anything else worrying. There hadn't been, so the signaler (after talking to the train manager too) re-opened the Up Main.
Shortly after the 2016 call I had my PTS re-cert course. When we got to the part where we were praciticing emergency calls I offered to instead repeat the actual call I had made a few months earlier. I was able to do so pretty much word for word I think!