In the second half of the '50s it is developed and the FS project takes shape for a new railcar that’s role is that of replacing gradually all that various different models under different grouping that formed the rolling stock of the FS. The Aln 668 had its official presentation and maiden voyage at the Milan Fair in the spring of 1960, after nearly four years of study. The initial presentation of the model went well, and since then over 785 railcars of this type have entered service with the FS. Another 100 approx. to this number were also produced for the private railways in concession, and another 500 approx. to foreign railways to be operated in  a full spectrum of latitudes.

A great machine, and attention paid to constant upgrading over the years, and tit can be said that they are the most present in the rolling stock of the FS, occupying approx. 75% of all railcars in use.

Meaning of the acronym Aln 668

A = Railcar (Automotrice)

L = Light

Diesel propulsion is n = (n stands for "Nafta" old word used to describe diesel fuel.)

68 = 68 seats

6 = double the initial figure 6 indicates the possibility of multiple command.

For the four-digit number that follows means the following:

first digit indicates the constructor (1 = FIAT)

the following three the progressive serial number.