Mexican State Railway class G-031
Mexican State Railway class GR-3
The G-031, sometimes also called GR-031, was a class of superheated Consolidations built for three-foot narrow gauge. It was based on the G-030 and basically had the same boiler. It had the same firebox, but less tubes to make space for the flues which held the superheater elements. The cylinders still measured 18 by 22 inches and the drivers still had a diameter of 41 inches.
Five were built by ALCO-Schenectady in 1936 and numbered 290 to 294. Numbers 295 and 296 followed in 1944. In the same year, the NdeM shops at Acámbaro built No. 297 to the same design. Between 1948 and 1952, the NdeM rebuilt all eight to standard gauge. They were now designated GR-3 and numbered 900 to 907. The class was retired in 1962.
Technical data
General
- Built
- 1936, 1944
- Manufacturers
- ALCO, Acámbaro
- Wheel arrangement
- 2-8-0 (Consolidation)
- Gauge
- 914 mm (Three feet); 1,435 mm (Standard gauge)
Dimensions and weights
- Wheelbase
- 5.77 m
- Total wheelbase
- 14.24 m
- Service mass
- 53.5 t
- Adhesion mass
- 49.9 t
- Total mass
- 94.3 t
- Rigid wheelbase
- 3.51 m
- Axle load
- 12.5 t
- Water capacity
- 13,627 l
- Fuel capacity
- 1 t (oil)
Boiler
- Grate area
- 1.737 m²
- Firebox surface
- 7.339 m²
- Tube heating surface
- 107.21 m²
- Evaporative heating surface
- 114.55 m²
- Superheater surface
- 31.494 m²
- Total heating surface
- 146.0 m²
Power plant
- Driver diameter
- 1,041 mm
- Boiler pressure
- 12.4 bar
- Expansion type
- simple expansion
- Cylinders
- two, 457 x 559 mm
Power
- Power source
- steam
- Estimated power
- 597 kW (812 PS)
- Starting effort
- 118.3 kN
Calculated values
- Factor of adhesion
- 1 : 4.14
- Optimal speed
- 31 km/h
- Power-to-weight ratio
- 11.2 kW/t
- Heating Surface Equivalent
- 214.2 m²
- Cylinder volume/HSE
- 1 : 856.45
- Adhesive weight/Total
- 1 : 1.07
- Tractive force/Heating surface
- 1 : 16.92
- Grate area/Heating surface
- 1 : 84.08
- Firebox/Tube surface
- 1 : 14.61
- Total/Superheater
- 1 : 3.64
