The Class D.445 is a class of diesel locomotives used by the Italian Ferrovie dello Stato (FS) railway company and by Trenord. 150 units were built between 1974 and 1988, divided into three series. History The D.445 represented an evolution of the FS Class D.443 locomotive, maintaining the predecessor's reliability and operational capabilities. At the beginning of the 1970s FS, during a plan aimed at the expansion and modernization of current service, designed a new version of an unified diesel locomotive which could also resolve the issue of supplying power to heat carriages in an efficient way through a high voltage 2,800 V head end power supply (REC) fed by a secondary generator. Previous diesel locomotives were not provided with this and so required the use of a generator wagon (Carro Riscaldo), leading to increased weight. The first series of locomotives, introduced from 1974, were built with curved front windscreens which would be later replaced by cheaper and sturdier flat ones. In 1979 a second series was ordered, fitted with the Italian standard 78 wire control equipment for use with driving carriages. At the end of the 1980s the whole group consisted of 150 units which allowed the retirement of the then old D.341 and D.342 locomotives. Description The locomotive follows the general unified characteristics of other engines about the chassis and mechanical design. The biggest differences are inside the electrical part: the two MTSC 039/19 DC motors (permanently in parallel) are fed by a three-phase AC generator (in place of a DC one as previous locomotives) through a Graetz Bridge. A high tension secondary DC generator provides a /2750 V output, able to supply enough power for 7/10 coaches depending on the type of climatising equipment installed. The prime mover is a diesel engine is produced by FIAT, type A210-12 supercharged with 12 90° “V” cylinders with a displacement of that produces at 1500 rpm. The engine is cooled by a forced circulation of cooling fluid through radiators with two hydraulically driven fans. The alternator is controlled by an electronic PWM control unit which is commanded by a 13 step regulator. The bogies are a monomotor design with a 'dancing ring' coupling, giving a B′B′ wheel arrangement. They are suspended by a flexicoil arrangement, with additional traction rods. Technical details 1st series units originally had curved windscreens, replaced in the 1980s by flat glas, later used on 2nd and