Data from Albert H Bone, "Some Recent Designs of Locomotives for Service on Continental Railways", Cassier's Magazine, 1910, pp. 561-609.
Bone notes that these were identical to the previous class of 2-cylinder, cross-compound Gruppo 630s locomotives save for the substitution of superheater flues and elements for the wholly saturated boilers of the earlier class of 62 engines. The Zara truck reduced the rigid wheelbase to 2.25 m (7 ft 4.6"). "In actual service," reported Bone,"these engines have shown a marked superiority over the compound engines of similar dimensions in coal and water consumption, especially with heavy trains." They were credited with a sustained output of 1,000 to 1,050 horsepower.
Data from "Locomotives for the Italian Government Railways," Railroad Gazette, Volume XLII [42], No 2 (11 January 1907), pp. 50-51; and DeGolyer, Volume 29, p. 125. Additional data from diagram published on DUEGI EDITRICE's TuttoTreno website [], a modelling site with a great deal of data. (visited 11 July 2004); and "Postcards showing two Baldwin-designed and built steam locomotive classes", Posted byu/Historynerd88
September 2021 on Reddit's r/TrainPorn at [], last accessed 13 March 2022. Works numbers were 28642 in July 1906; 28701, 28706, 28718-28719, 28763, 28804, 28827, 28833-28834 in August.
Baldwin built this set of balanced compound Ten-wheelers using metric measures, but othewise, according to the RG report, "...the general design of these locomotives follows American practice closely." One result was that these engines had the largest boilers of any Italian 4-6-0. The inside HP cylinders drove the front axle, while the outside LP cylinders drove the second and a single 15" (380-mm) piston valve supplied steam to each group of 1 LP and 1 HP cylinder on a side.
One significant difference in five of the class was the provision of a copper firebox in place of the steel furnaces found in most US locomotives by that time. Another difference, this time from most other four-cylinder compounds, was the provision of a shorter stroke of 610 mm for the inside HP cylinders vs the 660 mm for the outside LP. Still another was the more rudimentary shelter for the crew.
r/TrainPorn wrote that the class arrived in 1907 and was put to work on the Rome-Florence mainline, "but in the end the results were not good enough to justify further orders. " He added that while the Vauclain system "had its advantages ...it did not show a marked superiority to the Plancher engine." The experiment with steel fireboxes proved a failure, they "wore off awfully fast." He acknowledged that the problem "was partly down to issues with the German coal used, especially after WW I."
The Baldwins were gone by the end of the 1930s.
Principal Dimensions by Steve Llanso of Middle Run Media | ||
---|---|---|
Class | Gruppo 640 | Gruppo 666 |
Locobase ID | 8960 | 11407 |
Railroad | Ferrovie dello Stato (FS) | Ferrovie dello Stato (FS) |
Country | Italy | Italy |
Whyte | 4-6-0 | 4-6-0 |
Number in Class | 169 | 10 |
Road Numbers | 64001 a 64169 | 6661-6670 |
Gauge | Std | Std |
Number Built | 169 | 10 |
Builder | Berliner Maschinenbau | Burnham, Williams & Co |
Year | 1907 | 1906 |
Valve Gear | Walschaert | Stephenson |
Locomotive Length and Weight | ||
Driver Wheelbase (ft / m) | 13.78 / 4.20 | 13.45 / 4.10 |
Engine Wheelbase (ft / m) | 22.15 / 6.75 | 26.74 / 8.15 |
Ratio of driving wheelbase to overall engine wheelbase | 0.62 | 0.50 |
Overall Wheelbase (engine & tender) (ft / m) | 55.45 / 16.90 | |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 34,170 / 16,000 | |
Weight on Drivers (lbs / kg) | 97,665 / 44,300 | 98,987 / 44,900 |
Engine Weight (lbs / kg) | 121,408 / 55,070 | 146,001 / 66,225 |
Tender Loaded Weight (lbs / kg) | 73,855 / 33,500 | 100,090 / 45,400 |
Total Engine and Tender Weight (lbs / kg) | 195,263 / 88,570 | 246,091 / 111,625 |
Tender Water Capacity (gals / ML) | 3886 / 14.72 | 5280 / 20 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 5.50 / 5 | 6.60 / 6 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 54 / 27 | 55 / 27.50 |
Geometry Relating to Tractive Effort | ||
Driver Diameter (in / mm) | 72.80 / 1850 | 72.80 / 1849 |
Boiler Pressure (psi / kPa) | 169.70 / 1170 | 203.10 / 1400 |
High Pressure Cylinders (dia x stroke) (in / mm) | 21.26" x 27.56" / 540x700 | 15.55" x 24.02" / 395x610 |
Low Pressure Cylinders (dia x stroke) (in / mm) | 25" x 25.98" / 635x660 | |
Tractive Effort (lbs / kg) | 24,682 / 11195.58 | 20,289 / 9202.95 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.96 | 4.88 |
Heating Ability | ||
Tubes (number - dia) (in / mm) | 116 - 1.969" / 50 | 250 - 2.008" / 51 |
Flues (number - dia) (in / mm) | 21 - 5.236" / 133 | |
Flue/Tube length (ft / m) | 13.12 / 4 | 15.42 / 4.70 |
Firebox Area (sq ft / m2) | 106.52 / 9.90 | 150.16 / 13.95 |
Grate Area (sq ft / m2) | 26.90 / 2.50 | 33.37 / 3.10 |
Evaporative Heating Surface (sq ft / m2) | 1116 / 103.70 | 2169 / 201.51 |
Superheating Surface (sq ft / m2) | 361 / 33.55 | |
Combined Heating Surface (sq ft / m2) | 1477 / 137.25 | 2169 / 201.51 |
Evaporative Heating Surface/Cylinder Volume | 98.56 | 410.82 |
Computations Relating to Power Output (More Information) | ||
Robert LeMassena's Power Computation | 4565 | 6777 |
Same as above plus superheater percentage | 5661 | 6777 |
Same as above but substitute firebox area for grate area | 22,415 | 30,497 |
Power L1 | 8906 | 4875 |
Power MT | 603.11 | 325.73 |