I feel old. When I was a student, I would cycle to Hendon Beach in Sunderland. There I would see 36 HAAs being pulled by a 56. If I remember correctly, although there were trains from Wearmouth Colliery, the docks branch would be used for crew changes for the flows between collieries in Northumberland and the power stations in Yorkshire. Thought this was part of the continuing history of coal and railways which had started with the Londonderry Railway in 1854 and would go on long into the future.
However, all have now gone or been repurposed. So I think I might give Locomotion Models some of my pennies.