Franco-Crosti boiler

Where the loading gauge did not allow the feedwater heater to be placed beside the boiler it was mounted beneath.

Unlike the other Italian classes, these had a single feedwater heater mounted directly below the main boiler.

This Franco–Crosti steam locomotive is property of Trenitalia (the Italian national railways company) and assigned to D.R.S.

Pistoia (Deposito Rotabili Storici di Pistoia, which means Historic Rolling Stock depot in Pistoia) near Florence – Italy and managed by the non-profit association "Italvapore" Associazione Toscana Treni Storici In 1951 the Deutsche Bundesbahn (DB) rebuilt two Franco–Crosti boilered locomotives with two feedwater heaters located below the main boiler.

These thirty locos formed the new class 50.40 and proved quite successful economically but had problems with corrosion.

Like the German 50.40 these were 2–10–0 tender locomotives with a single feedwater heater under the main boiler.

The Crosti preheaters provided less improvement than had been expected, and were a problem for maintenance, owing to acidic fluegases condensing in the feedwater heater and causing corrosion.

All were converted back to a more standard form within a few years, the preheaters remaining in place, but blanked off.

In 1951 Oliver Bulleid was the chief mechanical engineer of the Córas Iompair Éireann and was experimenting with new forms of steam locomotive.

He converted a 1907 Coey locomotive to use a Franco–Crosti boiler similar to the original Italian designs and to burn peat.

The locomotive was a poor steamer and eventually was fitted with a forced-draught fan powered by a diesel engine carried on a wagon behind the tender.