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The reference for locomotives and railcars

Upper-Italian Railway class 1200

Rete Adriatica class 420, Rete Mediterranea class 480, and Italian State Railway class 420

Italy 1873 293 produced
Photo from FS times PD

For heavy service on mountain lines, the Upper-Italian Railway ordered eight-coupled locomotives from Sigl of Wiener Neustadt in 1872 which were similar to the Südbahn class 35. These replaced six-coupled locomotives and became a great success due to their simplicity of construction. They had outside cylinders and outside Stephenson valve gear. On an incline of 1.6 percent, they could haul 450 tonnes at 20 km/h and delivered an output of 620 hp. 

Production was also started at other manufacturers in Italy, Austria, Germany, Belgium and Hungary. In 1885, when 189 had been completed, they were split among the Rete Adriatica and the Rete Mediterranea and called class 420 and 480, respectively. The RM continued to order these locomotives until the total number had reached 293 in 1905. The last batches weighed around 10,000 pounds more than the first ones.

The FS took over the designation of the RA and still called them Gruppo 420. At the time when production was completed, they were already being replaced in heavy service in the mountains by 4-8-0 and 0-10-0 locomotives. Now, they were more and more used in secondary duties on level lines. Many continued to be used for decades, finally as shunters in ports. The last two were withdrawn in Piedmont in 1953.

Technical data

General

Built
1873-1905
Manufacturers
Ansaldo, Breda, Cockerill, Esslingen, Hawthorn-Guppy, Henschel, Maffei, MÁVAG, Miani, Napoli, Pietrarsa, StEG, Wiener Neustadt
Wheel arrangement
0-8-0 (Eight-coupled)
Gauge
1,435 mm (Standard gauge)

Dimensions and weights

Length
16.32 m
Wheelbase
4.10 m
Total wheelbase
10.02 m
Empty mass
45.9 t
Service mass
52.7 t
Adhesion mass
52.7 t
Total mass
79.3 t
Rigid wheelbase
4.10 m
Axle load
13.4 t
Water capacity
9,000 l
Fuel capacity
4 t (coal)

Boiler

Grate area
2.15 m²
Firebox surface
10.7 m²
Tube heating surface
163.48 m²
Evaporative heating surface
174.18 m²
Total heating surface
174.2 m²

Power plant

Driver diameter
1,220 mm
Boiler pressure
9 bar
Expansion type
simple expansion
Cylinders
two, 530 x 610 mm

Power

Power source
steam
Indicated power
456 kW (620 PS)
Top speed
45 km/h
Starting effort
107.4 kN

Calculated values

Factor of adhesion
1 : 4.81
Optimal speed
26 km/h
Power-to-weight ratio
8.7 kW/t
Heating Surface Equivalent
227.7 m²
Cylinder volume/HSE
1 : 1,182.16
Adhesive weight/Total
1 : 1.00
Tractive force/Heating surface
1 : 12.88
Grate area/Heating surface
1 : 81.01
Firebox/Tube surface
1 : 15.28
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