FS D341 & 342 Locomotives

FS D341 & 342 Locomotives

After the Second World War, the FS undertook considerable effort with regard to the modernization of the vehicle fleet. Among these, there was the need for modern vehicles that could travel the lines not yet electrified (especially in southern Italy), in order to be able to retire the steam locomotives.
The lack of experience and technique of the time led the FS to directly compare the diesel locomotives with hydromechanical motion transmission and the diesel locomotives with electric transmission, in order to be able to definitively choose only one path to follow.
All the major railway companies of the time were present on the battlefield, such as Fiat, Ansaldo, Breda and OM.
The diesel-electric locomotives were marked with the number 341, while the hydraulics received 342. The initial three-digit numbering was soon replaced with that of 4 numbers, in order to distinguish (through the thousands of digits) the origin of the construction of each locomotive (1000 = fiat, 2000 = breda, 3000 = om, 4000 = ansaldo, 5000 = reggiane).
As for the D341s, 17 units were initially commissioned by various companies (most of them Fiat).
The D342s were produced in very small numbers and, moreover, each company decided to follow a design style specifically for the locomotive bodies: Breda built only one locomotive (marked 2001), OM built two (3001 and 3002), Ansaldo built two prototypes (4001 and 4002).

Although hydraulic diesel locomotives had higher power availability than electric ones, their Achilles heel remained the gearbox: all series suffered from weaknesses, mainly due to problems related to transmission oil cooling. Electric diesels proved to be more powerful (less power loss with electric motor drives) and more reliable.
The D341 emerged victorious from the clash and the FS ordered a second batch of 85 locomotives (D341 second series).
On the other hand, however, not all was lost with the D342s: the Ansaldos proved to be the only ones with a sufficient reliability margin for the service to be performed; the FS commissioned the production of several units, for a total of 17 locomotives. The last three of the series were upgraded at the engine level, by installing intercoolers for cooling the compressed air from the turbine, capable of guaranteeing a power calibration of 100kw higher than the normal series.

All these locomotives are now demolished: the prototype versions are the first to be dismantled, due to an internal demolition order for all the prototypes in the 1980s. Some D341s are suitable for service for licensed railways or railway construction companies. The only D342 surviving and suitable for historical services is the 4010. Another unit is preserved in the Pietrarsa museum, together with a first series D341.

The Reggiane workshops took part in the “race”, building their own version of D341 (aesthetically the same as the others but with very powerful engines). The prototype version had serious reliability problems but, from the experience gained with that unit, this company was able to supply, following an order, 14 locomotives for the South East Railways (FSE), marked BB 151 – 163.

Power ratings from 970 to 1320kw
Tractive effort from 185 to 210kN
Max speed from 100 to 110km/h
Year from 1957