The trainsets of Greek State Railways A-200 A.300, A.320, A.400 and A.350 introduced from 1961 to 1967 placed on the standard line and number about 63 units, but all had little effect compared with the foreseeable needs.

For the supply of 20 new units, the American brand was again selected, this time, its Canadian branch, Montreal Locomotive Works.

[9] However, in the early years of the 1080's, the locomotives will have problems in their reliability, mainly due to material failure in cylinder heads and superchargers.

Their good specifications, ideal for freight trains, will lead the company's management to decide to keep these units in service for this purpose.

It is worth noting that even after ADtranz arrived[10] these locomotives were used occasionally on local trains, and many times, especially after their reconstruction, took over the traction of the 444-445 "Dostluk Ekspresi" (Thessaloniki Express) from Thessaloniki-Istanbul.

The reconstruction involved the removal of the steam generator and the configuration of the head-ons in the standards of the A-500 class locomotives and some other modifications and improvements.

After the return of the A-504 from the NREC facilities in Illinois, the then management of OSE decides to reconstruct them all in the style of the aforementioned locomotives.

Modern ergonomic controls and cabin air conditioning were installed in the N / H. Today, the last 2 units are at the Piraeus Factory and are awaiting completion of the works.

The livery of the locomotives consists of a blue horizontal stripe with a yellow border that ends in an orange-red arrow, covering the largest surface of the vehicles.