tractive effort formula

[andrewtoplis]

Hi All,

Does anyone know the formula for calculating the nominal tractive effort of a locomotive? Its in the Martin Evans book but I dont have a copy.

Thanks,

Andy

[gwrfan]

Hi Andy,

Here is the formula:

Tractive Effort =

B2 X S X P
__________ lb
........W

Where B is the diameter of cylinders in inches.

(B2 is actually B squared, but I couldn't uplift the 'B'!)

S is the stroke of cylinders in inches.

P is the effective steam pressure in lb. per sq inch.

W is the diameter of the driving wheels in inches.
( the dots are to enable me to keep the W in the centre!!)

If you need the rest of the pages, just holler and I'll copy it for you.

Geoff

[jackrae]

Surely there should be a factor relating to the number of cylinders. If this is for a 2-cylinder engine then a 3 or 4 should produce greater tractive effort.

Jack

[Richardw]

Whilst GWRFAN has quoted the formula in Martin Evans Book I have seen and used the following formula which gives results that match published T.E. figures for full size Locomotives that includes a factor for the number of cylinders.

Tractive Effort lb =

N x D² x S x P x 0.85
___________
2 x W

Where
N=No of Cylinders
D=Cylinder Diameter in inches
S=Stroke in inches
P=Bolier Pressure in psi
0.85 adjusts for the usual british practice of working out T>E> at 85% boiler pressure
W=Wheel diameter in inches

This formula has worked okay for the 2,3 & 4 cylinder types I have tried working out.

Regards
Richard

[andrewtoplis]

Magic!! Thanks guys.