The Class 735 was designed as a response of the situation developed during the years of World War I; the Italian railways needed more locomotives for freight trains, but there was no possibility of building them at home or in war-ravaged Europe.

Using the Class 740 design as a pattern (but allowing for alterations in order to avoid delays in the production),[1] an order for 100 locomotives was given to Alco in 1916, and the following year they were completed, disassembled and sent by cargo ship to Italy (with only 93 reaching Italy, however, as a U-boat sank the ship carrying the remaining seven).

Their American origin showed in their being fitted with a Bissel truck instead of the Italian bogie widespread in Italy, and with the locomotives of the first batch having fireboxes made of steel rather than copper.

Nicknamed "Wilson" (in honour of US president Woodrow Wilson) throughout their career, the Class 735 locomotives proved very successful; they were considered by engineers to be somewhat more powerful than the 740 Class, although their consumes were accordingly higher.

[1] Two Class 735 locomotives survived into preservation, 735.128, preserved as a static exhibit at the Pietrarsa railway museum, and 735.155, in possession of the Museo Ferroviario Piemontese, awaiting restoration.