by Benny
As usual, this topic only wants to give a survey of the matter, if you will have questions or specific requests ask and, within my limits, I will try to answer. Remember that italian dimentions are far smaller against the US standards.
Italy has been the cradle of railcars but main line diesel locomotives came relatively late because of various factors, the main one being how to transmit between the engine and the wheels a power far bigger than what needed for a small shunter or a light railcar. Other factors that retarded diesel traction have been the expected wiring of the last main lines, the low cost of coal against imported oil fuels and lightweight tracks and bridges in nearly all the secondary lines destined to remain without wires.
In the 50s, with the progress of technologies, became evident that the power transmission modes were only two: hydraulic, of north-european origin, and electric, developed mainly in the USA.
Having no experience in the field, FS asked to the main Italian builders for locomotives with a couple of two axle trucks, a power similar to the best steam locomotives and a light axle weight, to be declined with the two kinds of transmission making possible a comparison between them.
Fiat proposed D 341, a diesel-electric loco with a Fiat or Breda low speed prime mover of approximately 1000 kW and electric transmission derived from GE models, instead Ansaldo proposed D 342, a diesel-hydraulic moved by two Maybach high speed engines of 510 kW connected with Mekydro hydro-mechanical gearboxes of German-swedish origin.
The two models of locomotive were extensively tested in regular service but finally FS chose the electric transmission, officially because it is simpler than hydraulic one but really because of the lobbying of Fiat and CGE, the Italian filiation of GE.
After completion of the first D 341 order a second series of the project, with a different aesthetic and some different components, was passed to the industries.
To give work to Ansaldo a small batch of three more D 342, with improved power, was ordered too.
After the initial services, the first series D 341 became a familiar sight of southern Italy where they passed the operating life between local and freight trains and finished their services in the 80s. First series D 341.1007 waiting for the next service in Sibari, on the Ionic line, in the 80s.
The second series gone partly to the South but also worked from Rome and in Emilia Romagna and Veneto regions. The last ones operated from Taranto until the beginning of the 90s. Second series D 341.1024 at the head of a local service in Brunico (Pusteria valley), in the 70s.
D 342 instead, after initial services in Veneto and Sardinia regions, were assigned to Siena depot from where they were used on the non electrified lines of Tuscany with summer trips until Rimini through the Faentina line and Ravenna until the 80s when the class has been withdrawn. One unit has been preserved as historic item. D342.4005 entering in Florence Santa Maria Novella station to be hooked to its train in the 80s.
The three images are by W. Hardmeier courtesy of Photorail, probably the best site for italian railway photography.
Ciao
Italy has been the cradle of railcars but main line diesel locomotives came relatively late because of various factors, the main one being how to transmit between the engine and the wheels a power far bigger than what needed for a small shunter or a light railcar. Other factors that retarded diesel traction have been the expected wiring of the last main lines, the low cost of coal against imported oil fuels and lightweight tracks and bridges in nearly all the secondary lines destined to remain without wires.
In the 50s, with the progress of technologies, became evident that the power transmission modes were only two: hydraulic, of north-european origin, and electric, developed mainly in the USA.
Having no experience in the field, FS asked to the main Italian builders for locomotives with a couple of two axle trucks, a power similar to the best steam locomotives and a light axle weight, to be declined with the two kinds of transmission making possible a comparison between them.
Fiat proposed D 341, a diesel-electric loco with a Fiat or Breda low speed prime mover of approximately 1000 kW and electric transmission derived from GE models, instead Ansaldo proposed D 342, a diesel-hydraulic moved by two Maybach high speed engines of 510 kW connected with Mekydro hydro-mechanical gearboxes of German-swedish origin.
The two models of locomotive were extensively tested in regular service but finally FS chose the electric transmission, officially because it is simpler than hydraulic one but really because of the lobbying of Fiat and CGE, the Italian filiation of GE.
After completion of the first D 341 order a second series of the project, with a different aesthetic and some different components, was passed to the industries.
To give work to Ansaldo a small batch of three more D 342, with improved power, was ordered too.
After the initial services, the first series D 341 became a familiar sight of southern Italy where they passed the operating life between local and freight trains and finished their services in the 80s. First series D 341.1007 waiting for the next service in Sibari, on the Ionic line, in the 80s.
The second series gone partly to the South but also worked from Rome and in Emilia Romagna and Veneto regions. The last ones operated from Taranto until the beginning of the 90s. Second series D 341.1024 at the head of a local service in Brunico (Pusteria valley), in the 70s.
D 342 instead, after initial services in Veneto and Sardinia regions, were assigned to Siena depot from where they were used on the non electrified lines of Tuscany with summer trips until Rimini through the Faentina line and Ravenna until the 80s when the class has been withdrawn. One unit has been preserved as historic item. D342.4005 entering in Florence Santa Maria Novella station to be hooked to its train in the 80s.
The three images are by W. Hardmeier courtesy of Photorail, probably the best site for italian railway photography.
Ciao
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Last edited by Benny on Sun Sep 18, 2016 9:14 am, edited 1 time in total.
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