The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, and θ = Angle of inclination of crank to the line of stroke)

• m.ω2.r cos θ
• c.m.ω2.r sin θ
• (1 - c)m.ω2.r(cos θ - sin θ)
• m.ω2.r(cos θ - sin θ)