Yes we all have our own unique life experiences and memories to call on. As a youngster I travelled most on trains during the 1960s finishing in the early 70s, and then again for work in the mid 1980s, so our experiential eras just overlapped. I do vividly remember that change over period where 'modern' rolling stock started to appear and the rakes and rakes of sugar beat wagons, vans and other loose coupled stock laid up in nearly every siding in the country. Pick up freight wagons were still in operation in 1974 when I used to visit the local station in Newbridge and watch them uncoupling a single wagon from a goods train waiting in the loop while passenger trains past, and then roll it by man power into the goods shed for the local deliveries that day.
The other issue for me was 'toy trains' in the 1960s were inevitably either British passenger steam trains or steam hauled loose coupled British goods wagons, so I grew up with the concept of shunting wagons, pick up freight, and lots of operations arranging train formations, steam engine run arounds, turn tables, at the end of each movement, all requiring lost of interesting track formations and lots of point switching, etc, so todays fixed formation push-pull DMU passenger trains that just go back and forth seem very limited to operate, and fixed rake freight formations less interesting to operate.
I remember as a child getting a train set with two container flats and a few containers and 'spoiled brat' being secretly rather disappointed with the uniformity of a container train compared to a mixed goods train with vans, open wagons with all manner of loads, oil tankers, cable drums, steel flats, salt vans, grain wagons, coal, cattle, conflate, etc.
As you say modernisation from 1974 onwards was swift and very interesting in its own new way. The sugar beat trains from my memory back then seemed the longest freight trains and most common.
CIE Freight Modernisation