PIKE LAKE AND EASTERN

HARTFORD SHOPS

STANDARD 14

REVISED 06/01/03

The following calculations sizes the drive system for a locomotive.

A) ______ lbs Operating weight of engine

B) ______ lbs Total weight of cars

C) ______ lbs Total weight of passengers

D) ______ % % of steepest grade

F) ______ lbs Total train weight = A + B + C

G) ______ lbs Rolling resistance = F x .006

H) ______ lbs Curve resistance if E = 35 ft to 45 ft H = F x .008

if E = 45 ft to 60 ft H = F x .006

if E = 60 ft to 90 ft H = F x .005

if E greater than 90 ft H = F x .003

I) ______ lbs Grade resistance = D x F x .01

J) ______ lbs Total train resistance = G + H + I (tractive effort required)

we ignore wind resistance and accretion

K) ______ Coefficient of friction – wheel on rail, range 0.1 to 0.3

we assume 0.25 for dry rail, 0.1 for wet rail

L) ______ lbs Weight on powered drivers

CHECK L x K must be greater than J

M) ______ in. Drive wheel diameter

N) ______ in Drive wheel circumference = M x 3.1416

P) ______ MPH Desired travel speed

Q) ______ in/min Travel speed in inches per minute = P x 1056

R) ______ RPM Wheel rpm = Q / N

S) ______ lb-in Total axle torque required = (M / 2) x J

T) ______ HP Total hp required at wheels = ( S x R) / 63025

STANDARD 15

STEAM LOCOMOTIVE CALCULATIONS

REVISED 06/01/03

The following calculations sizes the drive system and boiler for a locomotive.

A) ______ lbs Weight on drivers (standard 14 L )

B) ______ lbs Drive wheel diamater (standard 14 M )

C) ______ MPH Desired travel speed ( standard 14 P )

D) ______ lb-in Axle torque required ( standard 14 S )

E) ______ lbs Tractive effort required (standard 14 J )

F) ______ in Cylinder stroke 2 x crank pin radius

G) ______ in Cylinder bore (enter if known otherwise calculate)

H) ______ PSI Boiler pressure

I) ______ in Drive wheel circumference = B x 3.1416

J) ______ in/min Travel speed in inches per minutes = C x 1056

K) ______ RPM wheel rpm = J / I

L) ______ HP HP required at wheels = (D x K ) / 63025

M) ______ PSI Mean Effective Pressure (MEP)

IF 85% cutoff = .98 x H

80% cutoff = .97 x H

75% cutoff = .96 x H

60% cutoff = .88 x H

N) ______ PSI Average cylinder pressure = M x efficiency

efficiency = 75% (losses in boiler piping)

P) _____ in Calculated cylinder diameter

CHECK G must be larger then P

Q) ______in/min Piston speed = K x F x 2

CHECK Q should be less than 3600 in/min

Boiler

R) ______ sq in Grate area = E / 3.5

S) ______ sq in Tube area = R / 8

T) ______ sq in Stack area = R x .06

U) ______ in Nozzle area = R x .005