In 1935 was the time of two small series (ALb 56.201-210 and ALn 56.2001-2010) of railcars with a better design, 56 seats, two engines powering an axle each one through Wilson gearboxes (that became a Breda trademark) and a speed of 140 km/h.
The two series were made to compare gasoline and diesel engines and differed only on it. They were moved by a Breda T 10 gasoline engine (studied for artillery tractors) or a British AEC diesel one built under license by the same Breda.
The Breda vehicles resulted more comfortable than the Fiat ones thanks to better bogies, the separation between passengers room and driving cabs and lower vibrations due to a more efficient suspension system.
In these series, as soon as in ALb 72.201-203, radiators were in the front ends and each engine had an half of the cooling surface at an extremity and the other half at the opposite one but the cooling system resulted the main problem of Bredas: because of the length of pipelines and the water pump directly moved by the engine (so depending of the revolutions), it was possible the rising of air bubbles that blocked water circulation and waves in the pipes that resulted in radiator plug explosion; instead, in cold weather, the excess of cooling damaged the front engine due to thermic shock (this is why Fiat units were equipped with a textile "bib" during winter).
To be noted that, at the same time, Breda produced also three van-railcars (ALDb 201-203) that, as the Fiat ones, had an ephemere life.
Definitely abandoned the gasoline engine, in 1937 began the series production (ALn 56.2011-2090)with various changes from the first units: the expansion braking left to the classic one on the rims, the engine was made entirely in steel and cast iron instead of having some parts in aluminum and, more important, radiators were put on the bogies and used only by the adjacent engine shortening very much the pipelines and changing the front ends that now only had some louvers to help air circulation.
Finally, between 1938 and 1940, were produced 140 units with multiple control and classified ALn 556.2201-2340.
During WW2 nearly all the railcars were dumped or used as coaches because of the fuel fault and because some engines were requisitioned to power navy units. Many of them were heavily damaged by bombings and in the afterwar, during reconstruction, the prototype series (ALb 56.201-210 and ALn 56.2001-2010), being non standard, were ceded, together with other units that FS considered not convenient to repair, to granted railroads that rebuilt them generally using GM 6/71 engines coming from US Army war remnants.
To solve the overheating problems and the fault of power of the AEC engine, Breda studied a radical modification that was implemented taking advantage of the recovery of damaged railcars. Engines were substituted with the model D17, a Breda evolution of the AEC with lower speed but 25% more powerful and a new water pump was installed. Radiators were put on the sides just at the back of the driving cabs and cooled by four electric fans each one. After these interventions the maximum speed was lowered to 120 km/h and problems diminished, though will be never eliminated.
So modified, the Breda railcars worked more than thirty years as the last services were around 1980. Being the Wilson gearbox very suitable for mountainous lines, they became a familiar presence in various central-southern branch lines as soon as in the Trentino Alto Adige region and depots of Fortezza, Fabriano, Sulmona, Benevento and Campobasso had decades of experience with the Bredas.
Today two units still exist: ALn 556.2331 is part of the historic fleet of FS foundation and ALn 556.2312 is a static exhibit at the National Railway Museum in Pietrarsa.
An unidentified ALb 56 Breda was shooted during a test run at Premosello, on the Simplon line, around 1935. Prototypes had radiators on the front ends. Photo by Breda, from the book of D. Molino and S. Pautasso "Le automotrici della prima generazione", Edizioni Elledi 1983.
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ALn 56.2079 is resting in Campobasso depot between two services in 1978. It's clearly visible the radiator on the side, between the cab and the door. Photo by B. Studer courtesy of Photorail.
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Mr. W. Hardmeier catch ALn 556.2332 and a sister leaving Brunico, on the scenic Fortezza to San Candido and Austria line in 1974. Note the alpine style of the station building and the three connectors for multiple control on the front end. Image courtesy of Photorail.
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