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Tractive Effort & Power

(of Steam locomotives)

The Tractive Effort of a steam locomotive can be calculated from the formula:-
(Normal locomotives only. Not appliable to compound locomotives.)

where:-: K = Factor for losses (^$); P = Boiler pressure; D = Cylinder bore

: S = Piston stroke; W = Driving wheel diameter; C = Number of cylinders

The Power output of a steam locomotive can be calculated from the formula:-

where:- K = Factor for losses (^$) P = Boiler pressure (PSI) A = Area of piston (sq.ins)	S = Piston stroke (ft) N = No. of power strokes per minute (^#)
(^$) Loss factor for cutoff, pressure drop in steam pipe, heat losses etc (approx 0.75 at 50% cutoff, 0.80 at 78% cutoff, 0.85 at 90% cutoff)
(^#) 2 per cylinder (for double acting pistons) x driving wheel RPM

Tractive Effort and Power Calculator
Enter either English or Metric values
below to calculate TE and Power.
[If both English and Metric values are entered for the
same parameter, only the English value will be used.]

1kg = 2.2046 Pounds 1 HP = 0.7457 kW 100 kPa = 14.5038 PSI	1m = 39.370 ins = 3.2808 ft 1 km = 0.6214 miles
Tyically use K=0.80 for saturated engines, K=0.85 for superheated engines. Note the accuracy of these calculations is not necessarily exact, and figures calculated here may vary from results published elswhere. They are calculated here from the formulas above. Results to be used at your own risk. Calculator provided for your personal use only.

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