The multitude of photographs I've seen suggests that the golden age of railways in Britain was the Edwardian era with immaculately turned out stations with armies of staff. The golden age of steam however would seem to come in a short period of time between the mid-thirties and the commencement of WWII when the emphasis was on power and speed.
1914: a golden age for photographers and shareholders maybe, and for the sheer diversity of steam operations and reach of the network.
But the railway ran pretty much on slave labour, and the business model was not commercially sustainable long term.
Nobody cared about the environmental or social issues of railways in the community (noise, dirt, emissions, working hours etc).
Safety was very suspect, still with wooden vehicle bodies and gas lighting.
As largely a monopoly provider, the railway was unprepared for competition first from road and then air.
Some timetables didn't change significantly between 1914 and Beeching in 1963.
I'd say 1914 was the peak.
The 1920s/30s were glitzy in places but this only applied to a small fraction of highly publicised services.
Of the Big Four, only Southern really got to grips with modernisation.
The LMS and LNER were still struggling with internal amalgamations in 1939, and the GWR was still stuck in 1914.
BR was the (clapped out) Big Four around the one table (sometimes), until Beeching.
There:take that! wink: