Italian State Railway class 741II
To increase the power and efficiency of the widespread 2-8-0 freight locomotive of the class 740, the idea was to rebuild it with a Franco-Crosti boiler. At first, 94 locomotives had been rebuilt between 1937 and 1950 with two feedwater heaters on the sides of the boiler barrel to form the class 743II. Then the class 741II was created in 1953 with a single feedwater heater below the boiler barrel. It could be distinguished from its predecessor by the single chimney on the right side of the boiler barrel.
By 1960, the Porta Vescovo workshops at Verona had rebuilt 81 locomotives to class 741II. In service they were concentrated in the north on the one hand and in Sicily on the other hand. In South Tyrol, sometimes three locomotives were used to haul 16-car express trains up the mountains. There their service ended in 1975. In Sicily, they were used a bit longer and retired in the early eighties. Today, two are still existing. 741 120 is operational and 741 137 is on static display at Pietrarsa.
Technical data
General
| Property | three-axle tender | four-axle tender |
|---|---|---|
| Built | 1953-1960 | |
| Manufacturers | Officina Grandi Riparazioni Verona | |
| Wheel arrangement | 2-8-0 (Consolidation) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | three-axle tender | four-axle tender |
|---|---|---|
| Length | 18.08 m | 19.89 m |
| Wheelbase | 7.30 m | |
| Empty mass | 59.8 t | |
| Service mass | 68.3 t | |
| Adhesion mass | 56 t | |
| Total mass | 100.2 t | 117.8 t |
| Rigid wheelbase | 2.60 m | |
| Axle load | 14.8 t | |
| Water capacity | 22,000 l | |
| Fuel capacity | 6 t (coal) | |
Boiler
| Property | three-axle tender | four-axle tender |
|---|---|---|
| Grate area | 2.8 m² | |
| Evaporative heating surface | 112.6 m² | |
| Superheater surface | 44 m² | |
| Total heating surface | 156.6 m² | |
Power plant
| Property | three-axle tender | four-axle tender |
|---|---|---|
| Driver diameter | 1,370 mm | |
| Boiler pressure | 12 bar | |
| Expansion type | simple expansion | |
| Cylinders | two, 540 x 700 mm | |
Power
| Property | three-axle tender | four-axle tender |
|---|---|---|
| Power source | steam | |
| Indicated power | 810 kW | |
| Top speed | 65 km/h | |
| Starting effort | 152.0 kN | |
Calculated values
| Property | three-axle tender | four-axle tender |
|---|---|---|
| Factor of adhesion | 1 : 3.61 | |
| Optimal speed | 32 km/h | |
| Power-to-weight ratio | 11.9 kW/t | |
| Adhesive weight/Total | 1 : 1.22 | |
| Tractive force/Heating surface | 1 : 20.27 | |
| Grate area/Heating surface | 1 : 55.93 | |
| Total/Superheater | 1 : 2.56 | |