The SPAP was formed in 1882 to operate the various sections of metre gauge railways then under construction on the Peloponnese peninsular and their connection over the Corinth canal and back through Athens to Piraeus. It controlled all sections of railway built on the Peloponnese, with one small exception, that is until 1951; when the SPAP took over the 12.4km Pirghos to Katakolon line which had operated as an independant company up until then. The SPAP subsequently took over the majority of the metre gauge Attica Railway to the east of Athens in 1929 although traffic on the line to Lavrion was never very great and it closed in 1956 or 1957. In wartime conditions the SEK took operational control of the SPAP from 10th June 1940. It was formally nationalised in 1954 and passed into the full administritive control of the SEK in September 1962. Prior to this in 1953 the SPAP had taken control of the North-Western Railway of Greece situated on the mainland across the Gulf of Patraikos from Patra and so for few years in the 1950s controlled routes totalling 865 kilometres.