Boring??? Sorry, I disagree! yes, the railways were a bit like to old Soviet Union but they coped with the transition from Steam, they dealt with Beeching, new working practices were being introduced.. But best of all was watching the prototypes and then the first production HSTs pulling out from Bath Spa Station in school break times! The best diesel train in the world, (in my opinion). BR was far more innovative than it was given credit for, and I will do BR Blue for all the reasons everyone has given to commemorate a heroically great era.
And, of course, I was born in '65 so grew up in the era!!!
Happy modelling whatever era and location you choose!