Back in the early/mid 60s I worked as student trainee with BR during the upgrade of Severn Tunnel Junction from semaphore to colour light signalling with the associated simplification of the track layout and vastly increased running speeds of the junction. Those couple of months were amongst the happiest of my life. The peak of my 'career' was when I finally got the knack of pulling off the up slow distant - a distance, if I remember correctly, of some 1.5 miles from the west box. An added surprise was when I received a phone call from one of the electricians a few months later to say that they were changing over the following weekend and to ask if I wanted to be there? I don't think I was the reason why it took a couple of months to sort out all the problems!
One thing that really impressed me was how, in the midst of a signalmen's strike, the local men made sure all the trains kept running with a minimum of delay. It took an in-depth knowledge of the rules to do that and they were proud of what they were doing. But these were Great Western men rather than British Railways.
I am glad, though, that I didn't take up a job with the railways. Generally moral at the time was pretty low and I never heard a good word said about the management.
My last memento from those days was a GWR signal finial which, sadly, was stolen from my garden some five years ago. (My collection of block equipment was loaned to a local preservation line in Bristol back in the mid 70s. I never got my receipt for it and later, when I tried to retrieve one item, the person who had collected it all denied any knowledge. I doubt that the society - now the Avon Valley Railway - ever saw it; I hope they did though, and put it to good use. It still rankles to this day.)