User:Steamenthusiast05/sandbox

Locomotive infobox


 * name          = FS Class 743


 * Powertype     = Steam


 * gauge         = standard gauge


 * tender type   = Three-axle or bogie


 * Fuel type     = Coal

The Ferrovie dello Stato (FS; Italian State Railways) Class 743 is a class of 2-8-0 'consolidation' steam locomotive, rebuilt from the FS Class 740 and were the first class of locomotive in Italy to be fitted with a Franco Crosti preheater system. This design although wasn't too successful as due to the numerous parts added to the locomotive the axle load was increased and so it caused this class of locomotive to be unable to travel on a number of routes due to unsuitable track conditions, another problem with this design was that due to the side mounted preheater barrels the loading gauge was pushed to a maximum limit. Due to these issues about 80 of the 90 of this class were re-rebuilt into class 741s, such class had the same 12% power increase as the 743 but thanks to the revised design both the overwhole width of the locomotive and the axle load were reduced hence enabling the engine to travel on a larger number of routes. In this version of the loco the preheater barrel was 1 instead of 2 and mounted underneath the boiler rather then on the sides, such design would also end up being used on the BR 2-10-0 9Fs class in the 60s.

Franco Crosti Pre-Heaters

The Franco Crosti Pre-Heaters was a system which took advantage of the hot exhaust gasses to pre-heat the water coming from the live steam injectors before it entered the actual boiler, this was done to improve efficiency as every time cold water is let into the boiler it will inevitably cool it down and so you will loose some steam pressure and will have to burn more fuel to regain it, and you can't even have hot water in the tender as injectors only work with cold water. with this system the water in the tender was cold and went through the injectors cold, but instead of going straight into the boiler, the water would be injected into (In the case of the 743s) two large barrels mounted on both sides of the boiler, these barrels much like the boiler it self had tubes going down their length in which the hot gases from the smokebox would flow down and slowly heat up the water surrounding them. These barrels were alway full of heated water to unsure that every time the injectors were used warm water would be fed to the boiler, once more cold water was pushed in by the injectors the water already in the barrels would have enough pressure to push trough the clack valves and enter the boiler.