thumb|Miani e Silvestri&C-A.Grondona Comi&C
thumb|Share of the Officine Meccaniche, issued 13 March 1930
thumb|right|OM Superba 665 1929
thumb|right|OM 120 truck
Officine Meccaniche or OM was an Italian car and truck manufacturing company. It was founded in 1899 in Milan as Società Anonima Officine Meccaniche to manufacture railway rolling stock and car production began in 1918. It disappeared as such in 1975, subsumed into Iveco, but still exists as a forklift builder.
Origins
The inception of the company resulted from the merger of two companies, Grondona Comi & C and Miani Silvestri & C in 1899. Originally, OM manufactured railway stock. Car production started in 1918, using the plant of the former Brixia-Zust (Brixia-Züst), just after OM took over Zust car company of Brescia, Northern Italy. The first OM car, the Tipo S305, was derived from an old Zust model. It appeared in 1918, fitted with a inline four-cylinder, side-valve engine.
The OM cars era
thumb|Poster Advertising OM Cars by [[Achille Mauzan]]
Further models were the Tipo 465, with a , in 1919, joined by the Tipo 467 () and Tipo 469 () in 1921. The model names reflected the number of cylinders (4) and the bore of the engines: . 1923 saw a new model, with an engine derived from the earlier four-cylinder models, the Tipo 665 'Superba' with a six-cylinder engine. This model was extremely successful in racing, winning top five positions in the class in 1925 and 1926 at the Le Mans but its greatest achievement was the victory in the first Mille Miglia race in 1927 where Ferdinando Minoia and Giuseppe Morandi led home an OM '1-2-3' finish at an average speed of for 21 hours 4 minutes 48 seconds. Some cars were equipped with Roots superchargers, while later models were bored and stroked to 2.2 and 2.4 litres - without changing the model name, however.
In 1925 OM began to build trucks and buses, using licensed Swiss Saurer engines and other mechanical components. Ties with Saurer persisted through all of OM's history. Passenger car production began to taper off, with some sources stating that production ended in 1932, with existing stocks sold for another couple of years. In total, 7,500 OM automobiles were built in about fifteen years. After passenger car had effectively ended, OM still displayed one last model: in 1934 the OMV, also called the Alcyone made the car show circuit. Equipped with hydraulic brakes, a full synchromesh transmission, and an engine with overhead exhaust valves, it never reached production.
Fiat take-over and post-war years
OM was taken over by Fiat in 1933 and the following year passenger car sales definitely ceased; OM became strictly a commercial vehicle and train parts manufacturer. The Titano was discontinued in 1968 and effectively replaced by Fiat's heavier trucks, the Fiat 619 and the . As with the lighter duty models, bus versions were also available of the Titano, called the "Titano P."