Tractive Effort Calculation for 4 Cylinder Compound 'Argentina'
Note: The figures presented below have been rounded to 3 decimal points to simplify presentation so may not give the precise answers shown when checking the figures. However these answers are valid when working to a higher number of decimal places.
The following lines of calculation as based on the formulæ given in 1936 by E.A.Phillipson in the book "Steam Locomotive Design: Data and Formulæ."
The formula used, which applies ONLY to 4 cylinder compound steam locomotives states:
Tractive Effort = 2(DxD)Sp / (R+1)W
Where:
D
= Low Pressure Cylinder Diameter.
S= Low Pressure Cylinder Stroke.
p = Receiver Pressure.*
R = Area of High Pressure Piston / Area of Low Pressure Piston.
W = Diameter of Driven Wheels.
*In addition it is stated that p shall be calculated thus:
p = P / (R+1)
Where:
P: Boiler Pressure multiplied by 0.8
Therefore in the case of 'Argentina' the figures, calculated in Imperial measures, are:
D = 22.835"
S = 22.047"
DxD = 521.418"
High Pressure Cylinder Area squared = 200.879
R = 521.418 / 200.879
= 0.385
p = (285x0.8) / (0.385+1)
= 228 / 1.385
= 164.590psi
TE = (2x521.418x22.047x164.590)
/ 1.385x50
= 3784199.078 / 69.262
= 54635.384lbs
Conversion from Imperial to Metric:
1lbs force = 0.004 kN
54635.384x0.004 = 243kN