Blue/Grey first gen DMUs, notably 101, 111, 114 classes.
Intercity 125s (when they were still branded as such), with a muddle of blue/grey coaches and swallow executive liveries - and that wonderful valenta scream, at once expectant and enticing, beckoning you to step closer and feel the fully glory and power of a magnificent class 43, but also slightly terrifying with the noise and blast of air that would come with it.
And then there were the pacers, a mixture of Provincial blue 142s and red/cream 144s, and the growing collection of sprinters which were decimating the old 'real trains' I'd known up until that point.
I guess I never really got over the loss caused by Sprinterisation.
I really loved the old first gen units with their buffers, droplights, quarter-light ventilators, bouncy seats, the odour of oil, the clunk of the doors slamming shut and the polished handles, even the dirt/dust lined seats, in their blue/green striped moquette s and the long disused ashtrays filled with discarded gum and sweet wrappers. It spoke of the old real railways, an echo of the days of steam perhaps.
The sprinters were just walls of sterile off-white plastic and windows that were too high to see from, and a few buttons to press. They felt like a train with all the fun taken out of it.