Epoch 1
Covering the years from the building of the first railways in the nineteenth century up to approximately 1920. Note the term ‘about’ as the Epoch system is intended to cover not just German railways but also other European systems.

Epoch 2
The years between the two world wars. It also lasted throughout the Second World War and came to an end during the years 1945-1948 depending on the country under consideration.

Epoch 3
1945 to about 1965-68. This era covers the last of the steam age and takes in the continental computerisation of stock numbering.

Epoch 4
The start of the modernisation periods from 1968 to around 1990.

Epoch 5
From about 1990 to the present day.