On the standard line, the A 201, A 301, A 321, A 351, A 401 and A 221 class locomotives had low power compared to the predicted needs.

To supply 30 new units, the American brand was again selected, but this time, its Canadian branch, Montreal Locomotive Works.

[8] Although in the early years they encountered engine problems, with a 12% drop since 1980, they remained the most reliable machines with the lowest degree of immobility.

Most actions take place inside and outside Thessaloniki on the lines of Athens, Kozani and Alexandroupolis, mainly freight.

It is indicative that after nearly 30 years of intense circulation they decided to rebuild them, they were almost all in full operation, except for A.502 and A.505.

Before the modifications, the vehicles were orange with yellow horizontal strips that ended up in triangles in the head-ons.