Data from "Locomotivas de Vapor de Via Larga"p. 28 , posted by Guarda Freio at 18:01, 23 September 2018, at [], last accessed 25 January 2026.
Apparently the shops like the Series 151's frame and drivers (Locobase 21320), but those are the only components that remained unchanged in this rebuild of six of the class in 1910-1913. Even the frame took a modification that extended it to accept a leading Bissel truck placed directly under the stack. A new roundtop held 30 more boiler tubes, both firebox and grate areas grew as did axle loading, adhesive weight, and engine weight.
The result proved unique as the class held the only Moguls to operate on Portugal's Castillian gauge.
Note on heating surface area:
NB: When tube heating surface area is measured using 45 mm (1.77") inside (fire side) diameter, total evaporative heating surface area including firebox amounted to 160.9 sq m (1,732 sq ft ). Locobase used the outside (water side) diameter.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 181 |
| Locobase ID | 21321 |
| Railroad | Caminhos de Ferro em Portugal (CP) |
| Country | Portugal |
| Whyte | 2-6-0 |
| Number in Class | 6 |
| Road Numbers | 181-186 |
| Gauge | Via Larga |
| Number Built | |
| Builder | CP-Lisbon shops |
| Year | 1910 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 11.81 / 3.60 |
| Engine Wheelbase (ft / m) | 21 / 6.40 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.56 |
| Overall Wheelbase (engine & tender) (ft / m) | 44.39 / 13.53 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 38,360 / 17,400 |
| Weight on Drivers (lbs / kg) | 104,499 / 47,400 |
| Engine Weight (lbs / kg) | 127,647 / 57,900 |
| Tender Loaded Weight (lbs / kg) | 60,186 / 27,300 |
| Total Engine and Tender Weight (lbs / kg) | 187,833 / 85,200 |
| Tender Water Capacity (gals / ML) | 2904 / 11 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 7.70 / 7 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 58 / 29 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 55.90 / 1420 |
| Boiler Pressure (psi / kPa) | 158.70 / 1080 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 18.9" x 25.2" / 480x640 |
| Tractive Effort (lbs / kg) | 21,722 / 9852.95 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.81 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 232 - 1.969" / 50 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 14.50 / 4.42 |
| Firebox Area (sq ft / m2) | 152.85 / 14.20 |
| Grate Area (sq ft / m2) | 32.29 / 3 |
| Evaporative Heating Surface (sq ft / m2) | 1887 / 175.31 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 1887 / 175.31 |
| Evaporative Heating Surface/Cylinder Volume | 230.61 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 5124 |
| Same as above plus superheater percentage | 5124 |
| Same as above but substitute firebox area for grate area | 24,257 |
| Power L1 | 4791 |
| Power MT | 303.23 |