PR EFA CE

A better understanding ofrailway devices by

the employe handling them , wo rks for economy

in railway service . This book on Locomotive

Lubrication is written for the express purpose of

bringingabout a better u nderstandingofthis very

important subject .Furthermore , a device such as the Locomotive

Force Feed Lubricator , which needs practical ly

no attention from the engineer , reaches the highest

efficiency in economy , in that it does not lubricate

per unit oftime , bu t in per unit ofworkdone by

the locomotive .

226072

3

Locom o tive LubricationThe aim of good lubricat ion is the reduction of

fri ction to a minimum .

The obj e ct of this work is to provide motive power

men with a basis for design ,supervision and regula

tion of lubrication on lo comotives,and it is hoped that

the information on this subj e ct,based on the results

of experiments,will assist in overcoming some of the

obstacles met with in lo comotive lubrication .

Friction .

Friction is the force that acts b etween two s u b

stances in contact,opposing their sliding one on the

other,and

'

is caused by the irregular surfaces of the

two bodies interlo cking . %nder the microscope the se

irregular surfaces appear inter lo cked somewhat as

shown in the following illustration

enrt <of friction is the ratio of the force ,r eqitirie ide

i

ia‘

cbody c along a horizontal plane sur

face to the weight of the body .

From the definition of fricti on it is evident. that it

is a, loss of power in operation of the lo comotive,and

its reduction,therefore

,must be considered primarily

in connection with the cost of maintenance,Operation

and d elays,an d the safety of tran sportation .

Cond itions Affecting Friction .

The amount of friction depends

First—On the nature of th e substances in contact %Second—Ou the pressure with which these two sub

stances are held in contact

Third—The speed of their moving,one on the other %

Fourth—The temperature of the substances in contact %Fifth—The substance b etween the two

,put there t o

reduce th e amount of friction .

Estab l ished Laws of Friction .

Fir s t% W ith substanc es in contact va r iabl e and

all other conditions constant there is no fixed law,the

amount of friction depending on the nature of sub

stance s in contact .

Second % W ith varying pre ssures and all other cond ition s constant

,friction increases directly with th e

pressure .

Thi r d % W ith speed variabl e and all other cond ition s constant

,th e friction decreases at speeds from

10 ft . to 100 ft . per minute,but at h igher speeds it is

nearly directly proportionate to the square r oot of

the speed .

Fou r th . W i th varying temperature,and all other

conditions constant,the amount of friction decreases

as temperature rises unti l abrasion takes place .

Fifth % W ith substanc es to reduce friction variableand all other conditions constant

,the r e is no fixed

law,the amount of friction depending on the nature

of substance u sed as lubricant .

Friction—Lu b ricants .

The lubricants used in lo comotive prac tic e consist

of different oils,grease

,graphite and lead used sep

ar atel y or in combination . It has b een found that

each of these has certain advantages over the oth ers

for th e l ubrication of differen t parts of th e lo comotive

mechanism . The general qual ifications of a good l n

b r ican t are given by Mr . W . H. Bailey,in Proc . Inst .

0 . E .,vol . l .

,p . 372

,and are as follows

1 . Sufficient body to keep the surfac es fre e from

contact under maximum pressure .

2 . The greatest possible %uidity consistent with

the foregoing condition .

3. The lowest possible coefficient of friction,which

in bath lubrication would be for fluid friction app r oxi

mately

4 .

i

The greatest capacity for storing and carrying

away heat .

5 . A h i gh temperature of decomposition .

6. Power to resist oxidation or th e action of th e

atmosphere .

7. Freedom from corros ive act ion‘on the metal s

upon which based .

Lubricating material made up of any number of

el ements havin g independent qualific ation s,must b e a

homogeneous who l e and remain so under the condi

tions surrounding th e problem .

In considering qualifications Nos . 1 and 2,the cohe

siven ess , or visco sity , of the lubricant must. be sufficient

to prevent the separation of its parti cles,and the ad

h esion of the lubricant must be sufficient to enable it to

cling to the bearing surfaces . A lu bricant having

greater adhesion or cohesion than the above conditions

require,will increase th e fric tional resistance .

Considering the friction developed between two su r

faces lubricated in on e case with grease and in the other

with oil,the friction developed with grease is greater

than with oili

for the following reasons

FIRST % When the grease is cold,i ts cohesion is

greater than oil,and its adhesion to the bearing surfaces

is less,and consequently the coefficient of friction is

higher .

”

5

SECOND % When the grease is in a %uid,or semi

fiu id state , its cohesion , while less than when solid , is

again greater than oil,and its adhesion to the bearing

surfaces,while greater than when solid

,is again less

than oil,and consequently the coefficient of friction is

higher % and further,addition al friction has to be ex

pended to furnish the heat required to reduce th e solid

grease to a %uid state .

It is an undisputed fact that the generation(

of heat

by friction is an extravagant method .

A n abstract of a brief historical review of lubricants,

that have been used in l ocomotive practi ce,as given in

the American Railway Master Mechanics ’ Proceed ings,

% ol 42,1909

,follows %

In the early years vegetable oils (principally olive

oils% were used for machine lubrication in Europe ,and

,alth ough history is vague on this subject , i t is

fair to assume that the first steam locomotives were

lubricated with oils of this kind .

”

% The-r e have been times in the history of st eam

lubrication when anything of a greasy natu r e was con

sid er ed a lubricant and experimented with . In the

early er a of st eam locomotives in this country a rail

way publication,under the caption

,

‘Pork for Journal

Boxes,

’ stated % Why not use it% We have asked 50

railway men within as many days if they were aware

of its success . On the H. R . R . a car was packed with

slices of fresh pork,and is today as i t was a year ago .

Th e cos t per box for pork packing , that wil l stand at

least a year will not exc eed 30 c ents .

%

A railway man wh o used soft soap as a lubricant

seemed,to say th e l east

,ec c entric . A standard auth

or ity ,

‘

D. K. Clark ’s Railway Machinery,

’ published

in 1855,said %

‘

In proportion as the bearing surfaces

ar e fine,hard and pol ish ed ,

i

th e more %uid may be the

lubricating material % (thus fine oil may b e us ed ih

st ead of soap .% It is probable that concussion was

originally the inducement to use soap on railways apart

from the diffi

culty of preventing oil from being

wasted .

Antedating the use of mineral oil,cotton seed and

sperm oil were extensively used,followed by a more

general use of lard oil for machine lubrication and

tallow for,

valves and cylinders . A s early as 1854 a

firm in Philadelphia introduced what they termed a‘

lubricating grease adapted to use on al l classes of

running stock on railways .

’ They recommended it on

account of its ‘fre edom from gum or glutino u s sub

stances and adaptability to all kinds of weath er .

’

The mineral oils or p etroleums were placed upon

the market in the vear s soon fo l lowing and on account

of their cheapness and superiority as a lubricant their

use became general . The natural West % irginia oil

with its notable characteristic s of a low cold and a

high fire test,immediately found favor and was con

sid er ed superior to sperm . The produc tion of theW est% irginia oil was limited

,and as the demand rapidly

increased the supply was soon exhausted . A manu

factu r ing concern in 1869 introduc ed for railway serv

ice an oil for external lubrication,combining the ex

cel l en t qualiti e s of nature’s best lubricating product

with other ingredients,producing an article which

met all of the requirem ents of the day % an oil of l ow

cold and h igh fi r e t est . a gravity permitting a ready ,

%ow,and the sustaining power for support of the ever

increasing loads upon the bearing surfaces . This l n

b r ican t has stood the test of servi ce from the date of

its introduction and is now used on the maj ority of the

10

railways of this country,as well as .on many of the

English and European l ines .

”

Prior to the introduction of mineral cylinder oil,

tallow was the almost universal lubricant for valves

and cylinders . In some few instances% oil mixed

with plumbago was used,and grease introduc ed

through cups with double stop cocks was tried,but

melting tallow in the old familiar tallow pot was p r ac

tic ally the universal practic e for many years . Tall ow

ca r rying a high percentage of acid was found ob jec

tionab'

l e,the acid attacking the metal

,pitting and ren

dering it porous and weaken ing its structure .

”

% The superiority of an oil fre e from acids,with

greater viscosity,le ss liable to gum

,an d with a highen

fire test to meet the increase s in temperature was fast

relegating tallow to'

other uses . In 1870 there was

plac ed upon the market a cylinder oil me eting all the

desired requirements,furnished from a sourc e of sup

ply that insured uniformity in qual ity and quantity

to m eet all demands . This cyl ind er oil has stood the

test through all the gradation of temperature as steam

pressures have increased from 120 to 230 lbs .,and

higher temperatures incident to th e use of superheated

steam .

Mr . Wm . J. Walsh made a statement in a paper onLubrication of Railway Equipm ent

,

” presented b e

fore the New England Railway Club which in part is

as follows %‘The average running temperature of freight

trains is considered to b e 80 degrees,and the average

running temperature of passenger trains 125 degrees .

11

We learn from experienc e that the proper gravity of

oil for the lubrication of all trains should be about ‘

30

degrees,and as a degree of% gravity is lost at every ten

degre es advanced in heat,it is plain to be se en that

should we supp l y an oil for the lubrication of a freight

train at 80 degrees,with a gravity of 30 degre es

,and

if the same lubricant is used on a fast - moving passen

ger train at 125 degrees,the gravity of the lubricant

would b e reduced about 5 degrees % or , to explain fur

ther,if this lubricant at 30 degrees gravity is dense

enough to carry the load at 80 d egrees running tem

per atu r e , it would not be dense enough to carry it at

125 degre es running temperature .

”

The use of grease as a lo comotive lubricant has been

proved by tests to result in an increase of friction over

oil . There have been reasons,howev er

,for it s use in

lo comotive practic e .

The succ essful operation of oil waste driving j our

mals requires the cellars to be dropped every ten to

twelve days,at an actual labor cost of 35e per box

,to

facilitate insp ection and repacking when necessary .

The following is quoted from a paper by Mr .

J. R . A lexander,General Road Foreman of Engines

,

Pennsylvania R . R .

,read before th e Railway Club of

Pittsburg

The economical operation of locomotives also de

mands careful supervision of the methods employed in

handling lubricating oils,for surprising as it may ap

pear,there are many men who believe good lubr ic ation

can best be obtained by quan tity rather than quality .

12

The ideal condition insuring perfect l u b r ication’

on lo co

motives is to have a lubricant,th e globules of which will

be sufficiently strong,and the m echani cal arrangement

such that the load carried on the bearing will not forc e

out the film of oil,thereby permitting metallic contact .

”

Graphite is a good lubricant,especially under high

pressure . It is n ot adaptable to locomotive lubri cation,

b u t i ts use with water or a light oil as a carrying

medium presents possibil it ie s of development . It gives

a l ow co effic ient of fri ction with cast iron or other po

r ou s m ater ial s by fillin g the minute irregularitie s in the

surfaces,thus increasin g the actual bearing area .

Friction - BearingMetals .

A s has been stated above , the n ature of the bearing

m etals determines the amount of friction between them

when other conditions are constant . Whil e there is no

certain rel ation between the mol ecu lar structure of the

bearing and friction,it is generally true that the harder

and smoother or more polished the metals,th e lower is

the friction developed,due to the surfac es of the metals

having fewer irregularities to interlo ck or overlap each

other . With metals harder than brass for bearings,

such as cast iron,a j ournal is more liable to cut and

wear . Such bearings do not adjust themselves as read

ily to irregularities of the journals,an d in some cases

they are too brittle to withstand stresses.

In the June , 1905 , Proceedings of the American Society of Mec hanical Engineers , Melvin Pric e stated his

13

conclusions on this question as follows % An alloy ’s

resistance perform anc e seems to be pe culiar to itself ,

a l though there ar e often partial similariti es . Investi

gation showed that there was no definite law between

friction and the structure of alloys .

”

The desired qualities of soft and hard bearing

metal s are ably discussed in a report by Prof . R . C.

Carpenter in % ol . 27 of the Society of Mechanical Engin eer s on % Locomotive Bearings

,

” from which we quote

the following %

Des ir ed %u al ities .

Th e qualitie s which a bearing metal should have

in order to be satisfactory are qu ite varied in nature,

an d in some respects somewhat contradictory . The

bearing metal should first of all b e one that has con

sid er ab l e adhesion for a lubricant and is readily wetted

by it . It should also be softer than the shaft which it

supports,so that in case of lack of lubrication

,or in

case hard gritty materials get in the bearing , the bear

in’

g material would be injured rather than the j ournal .

It should be hard enough ,however

,to retain its shape

under any conditions of pressure or t emperatur e which

are likely to b e imposed upon it by actual use . The

melting temperature of the b earing metal should be

less than that of the j ournal which it supports , but

should not at the same time be readily mel ted by

changes in temperatu re which occur in practic e . The

bearing metal when melted should not possess the

property of adhering or we l ding fast to th e j ournal .

”

4

Soft Metal s .

For many purposes where th e pres sures are l ow

an d temperature not likely to get high,a very soft

bearing metal,such

,for instance, as may be made

from 85 p er cent lead and 15 per c ent antimony , is

exc ellent . This metal is,however

,entirely unsuited

for hard service, as it readi ly changes its form with

increases of temperature . The bearing metal known

as genuine babbitt,consisting of tin 85 to 89 per c ent ,

copper 2 to 5 p er cent , and antimony 7 to 10 per cent ,is probably adapted to a wider range of use than

any other metal which has ever been designed or in

vented . On account of the large amount of tin ,this

metal is expens ive , an d ther e is a great temptation to

palm off as a substitute a metal containing a consider

ab l e portion of lead . A s a result of my experience , a

considerable amount of l ead can b e used,provided it

alloys perfectly with th e other metals and does not r en

der th e compound too soft . Lead is,however , a poor

conductor of heat % for a given condition of lubrication

and work performed,a bearing metal containin g much

lead is likely to run warmer than on e containing other

metals .

”

%

The soft metals mentioned above pos sess th e ad

vantage that they can be easily melted and cas t into

shape in place as desired or as needed for u se on th ej ournal . ”

Har d Metal s .

There are a number of other metals which have

a high melting point and quite a large co efficient of

15

contraction which,if used for hear ing metals

,must

b e cast in separate moulds and finished on machine

tools before applying . These metals vary in hardness

to a considerable ext ent,the phosphor bronze being

probably the hardest and the yellow brasses the soft

est . I made extensive experiments with a bearing

metal of this class c onsisting of an alloy of aluminum,

zinc and copper,th e zinc b eing largely in excess of

the other ingredients . That alloy was ver y' \

satisfac

tory when zinc of the proper purity could be obtained ,but was so much affe cted by the impurities likely to

be found in zinc that it was frequently quit e u n satis

factory in practice .

”

%I have found that a mixture consisting of 50 per

cent of aluminum,25 per cent of zinc and 25 per c ent

of tin forms an alloy which has many excell ent prop

er ties as a bearing metal . It is light in weight , has

a fair degree of hardness,a moderatel y high melting

point,and

,so far as I can determine from laboratory

experiments and some practical applications , is a su

perior metal for certain kinds of b earings .

”

Con cl u s ion .

From the uncertain nature of our methods of

te sting and from the varied conditions under which%

bearing metals are used , i t i s easy to understand the

differences of opinion which are held by various en

gin eer s regarding the quality of the same bearing ma

ter ial . This fact also probably explains the reasons

why such a variety of pric es and grades of bearing

metal can be market ed .

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Lu b rication—Driving Journal s .

Tests have be en made proving that driving journal

friction increases proportionately as the distance trav

cl ed after oiling .

The lubrication of driving j ournals with oil by

cups an d c ellars caused so much trouble in locom otive

operation,due to the increase in length of runs

,periph

eral speeds and bearing pressures combined with the

lack of a regular fe ed of the lubricant,that grease was

resorted to by some railroads because i t afforded a

positive feed,which materially reduced the annoyances

and expense of hot. driving j ournals .

When the first experiments were made with grease

it was found that the grease c ellars,with the usual

oil - hole l eft in the top of box and with the brasse s fit

t ing the j ournal as snugly as was the practice with

oil,would not give satisfactory results . In these ex

per im en ts it was found that the grease was forced out

through the hole in the top of the box . In a number

of instances wooden plugs were driven in th e holes to

prevent this,but the pressure exerted by the revolving

j our nal forced these plugs out,demonstrating the mag

n itu d e of th e pressure thus generated . On e explanation

of this pressure is that the revolving j ournal in gen er at

ing pressure acts l ike a paddle - fan water wheel r e

ve r sed in that the minute irregularities on the surface0 of the j ournal fill with the lubricant and carry it to

the pressure side of the brass where it adds to th e

amount previously taken up and retained % a kind of

cumu lative pressure which continues until the pressure19

has reached a point that will not permit more grease

entering between the j ournal and the bearing .

A fter these grease difficult ies were overcome,the

loss of trac tive force,with the consequent higher cost

of operation per ton mile hastened the perfection of

the automati c oil forc e fe ed lubricator for j ournal

lubrication .

The following is another quotation from Mr . J. R .

Alexander ’s paper%

Driving box lubrication is obtained by means of a

supply of oil fromboth top and bottom of the journal,

while tender and car j ournals depend altogether on the

supply of lubricant from the under sid e . In either case ,however

,it is essential that the packing in j ournal box

cellars be maintained in good condition,and to this

end it is necessary that a good qual ity of wool waste,or

other suitable material , be provided and same prepared

for use by b eing submerged in oil for not less than 48

hours,after which the waste should be drained of free

oil in excess of 4 lb . oil per pound of waste , and fur

n ish ed to inspectors well loosened up and not wrapped

up tightly in balls . In packing j ournal boxes it is a

great mistake to have the waste contain too much free

oil,as this makes it impossible to pack sufficiently tight

under the j ournal to prevent pounding down after loco - s

motive or car is in motion . Du st guards at back of

journal boxes should be main tained in good condi tion

and the packing kept firmly set up to the journal at the

rear of the box . A t the sides the waste should not be

allowed to extend above the center line of the j ournal,

for if the waste is allowed to pack against the ris ing side

20

of the bearing it will soon become glazed and'

act as a

wiper,and is very likely to clean the j ournal free of oil

,

preventing it from passin g under the hear ing. The

best results and with considerable economy l n the amount

of oil and was te,will b e obtained by having locomotive

an d ten d er'

jou r nal box cellars not more than in .

deep,as experience proves that capillary attraction will

not bring sufficient oil through waste from a greater

depth .

’

In reference to the above it might be stated that aver

age wool was te und er most ' favor ab l e conditions seldom

absorbs over 3 lb . oil to 1 l b . waste .

Lu b r l cation—% al ves and Cy l ind ers .

The question of internal lubrication has be en given

additional consideration in rec ent years,due to in

creasing difficultie s met with in high ste am pressures

and superheated steam with irregular lubrication .

The lubrication of valves and cylinders to be effec t

ive must b e regular and in proportion to sp eed and

cut off,b ecause one of the fu n d am en al laws of fric

tion is,as previously s tated

,that it directly

as the speed of the moving parts up to100 ft . per

minute and increases nearly dire ctly proportionate

to its square root at greater speeds . This applies to

valve an d cylind er as well as j ournal lubrication .

% alve and cylinder lu brication should be proportionate

to the cut - off at which the lo comotive is working b e

cause at the longer cut - off th e valve travel is greater

and while piston travel is the same the mean effective

21

pressure and cons equently the temperature in the cyl %

inder is greater , both of which conditions require more

lubricant . In addition to this there is the increased

tendency to work water at the longer cut - off when

starting .

Driving j ournal lubrication should be proportionate

to the cut - off for the reason that at longer cut - offs the

mean effective pressure in the cylin der is increased,

thereby increasing the pressure on the working sides of

the j ournal bearing .

Relative to the amount of l u b r 1can t necessary the

Committe e on Locomotive Lubrication of the Ameri

can Railway Master Me chanic ’s A ssociation in 1907

made the following recommendation%% our committee fe els that for internal lubr ication

70 miles per pint for large freight locomotives and 80

miles per pint for large pass enger locomotives se ems

to be the amount needed to lubricate pr operly . The

amount to each class depends upon the speed at which

the locomotive i s running % in bad water districts

the oil allowance should be increased about 25 per

cent .

”

Lu b rication—Su perheated Steam .

Oil must b e fed regularly to overcome the d ifficultyof lubricating valves and cylinders

,in the case of sup

er h eated s team ,b eau se of th e lo ss of lubrication due

to th e dryness and high temperature of the steam it

self. Th e fact was emphasized in th e 1907 Proc eed

ings of the Traveling Engineers ’ A ssociation ,and au

22

tomatic force feed lubrication was recommended . Th e

fastest superheat ed lo comotive in the world is l u b r i

cated by an automatic forc e feed system .

Lu b rication—Regu lar or Irregu l ar .

Irregular lubrication necessitates using an exec s

sive amount of oil,causes unnecessary friction which

results in most of the hot b ear ings an d cut surfaces,

and in the case of valves and cylinders materially

affects the proper distribution of steam by overburden

ing the valve gear .

These conditions increas e the cost of operation by

increasing coal consumption and by d e creasing the

available power of the locomotive . Th e overtaxing of

the valve gear also cause s more rapid wear of pins an d

connections and earlier repairs .

Method s of Lu b rication—Hand Oi l ing—Oil Cu ps .

A t the outse t the m oisture of l ow pressure steam

was depended upon to lubricate valves and cylinders ,but soon oil cups were placed on steam chests ,and were filled whenever stops were made . The next

st ep was to plac e the oil cup in the cab of the loco

motive,so that it could be operated by th e enginemen .

This method . of lubrication was nothing more than

hand oiling,but it was more convenient .

Method s of Lubrication—Sight Feed , Hyd rostatic .

The second step in valve and cylinder lubrication

taken about twenty - five years ago , was the introduction

of the hydrostatic sight feed lubricator . The principle

23

upon which it operates is,that a column of water under

b oiler pressure forces the. oil %oating on top of it into

cylinder oil pipes leading to the b earing surfaces . The

difference in pre ssure which forces the oil is equivalent

to the weight of a column of water equal in height to

the difference in l evels of lubricator outlet and b ottom

of choke plu g,le ss the friction in the pipe

,plus the

difference between boiler and st eam chest pressure .

Method of Lu b rication—Force Feed .

Force feed lubricators were p erfe cted first for sta

tion ar y engines and a u tomobiles , and about five years

ago the lubricator with automatic features was finally

designed for locomotive service . The European rail

ways have used forc e feed lubrication much longer,

b u t the mechanical construction of the lubricator did

not appeal to American engineers,especially on ao

count of the increased consumption of oil due to the

impossibility of fine adjustment of feed.

W ith the modern American system of automatic forcefe ed lubrication

,motion is obtained from some part of

the valve mechanism,the motion of which is propor

tion al to that of the valve its elf,and is transmitted

through a mechanical transformer to the lubricator

proper,lo cated in the most convenient place on the

lo comotive . Individual pumps force the oil through

individual pipes to the h ear ings to b e lubricated . The

lubricator operates automatically only when the engine

is running,and the speed of the plungers in the l u b r i

cator is entirely dependent upon the travel of the

valve .

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also in proportion to the cut - off at which the engine is

being worked . It i s automatically regulated by the

speed of the engine and the position of the reverse

l ever .

Power and Tractive Force - Lu b ricants .

A good lubricant applied in regular sufficient quanti

ties reduces th e internal friction of a lo comotive there

by increasing the effective tractive force and horse

power . The tests made by the Pennsylvania. Railroad

at the Louisiana Purchase Exposition demonstrated

that the u s e of grease instead of oil on driving j our

nal s,increas ed the friction per j ournal by from 75 per

cent to over 100 per cent,dependin g on the peripheral

speed .

The report of Prof . W . F . M. Cross,printed in the

1906 proce edings of the American Rai lway MasterMechanic ’s A ssociation

,is here quoted in part

%A c cepting the oil lubrication as a basis ofcompari

son it appears that at 20 miles an hour the loss of power

resulting from the use of greas e is slight,so small in

fact as to be almost negligibl e,b u t as the speed is

increased the loss is increased and at 60 miles per hour

it amounts to from 140 to 160 horsepower . The equiv

aleut coal loss,assuming four pou nds of coal per horse

power hour,is something more than 500 pounds per

hour . A summary of results in form permitting easy

comparisons is set forth in the ac companying tabl e .

Sp eed ofE ngin e 20 Mil es an Hou r .

Pounds pull of the draw - bar necessary to over

come friction of the engine .

Cold start Grease Oil

Hot start Grease Oil

Average

Tractive forc e lost by u se of grease

Horsepower lost

Coal lost per hour r u n (assuming 4 pounds p er

horsepower hour%

5 0 Mil es an Hou r

Pounds pull at the draw - bar necessary to over

come friction of the engine .

Cold start Grease Oil 555

Hot s tart Grease Oil 780

Average

Tractive forc e lost by use of grease .

Horsepower lost

Coal lost per hour run (assuming 4 pounds per

horsepower hour%

60 Mil es an Hou r

Pou nds pull at the draw - bar necessary to over

come friction of th e engine .

Cold start Grease Oil 655

Hot start Grease Oil 873

Average

27

2 Tractive forc e lost by use of grease

Hors epower lost

4 . Coal lost p er hour run (assuming 4 pounds per

horsepower hour%

These tests were made on an A tlantic type l ocom o

tive with greas e and oil used in each case on driving

j ournals and crank pins .

W e ar e informed that oil was fed to driving j ournals

by gravity through holes in the top of the driving

boxes . These hol es released whatever pressure the

revolving journal generated % thus relying for lubrica

tion on the littl e amount of oil that,due to its adhesive

quality,could not b e forced out from between the j our

nal and th e bearing .

The modern automatic force feed method forces the

oil into the top of the driving box against the pressure

generated by the revolving j ournal an d raise s the box

from the journal as far as the oil packing on the ends

of the driving box will allow , thus separating the j our

nal and the b earing with a th ick film of oil . This fills

all irregularitie s in the bearing surfaces,so that the

actual bearing surfac e more closely approximates the

proj ected areas . It separates the j ournal and bearingsufficiently to clear proj e ctions on one or the other that

would ordinarily cause cutting . There are actual cases

of cut j ournals thus lubricated,running as cool as the

smooth j ournals on the same engine .

In experimenting with a driving box in the labora

tory it was found that a gauge piped to the cavity in

the top of the brass recorded a pressure as high as four

28

times the bearing pressure per square inch that the

weight on the bearing divided by the proj e cted area

should have given,which proves that the actual

pressure per square inch is a very different quantity

from that figured from the proj e cted area . The l n

creasing of the realized area by intervening a thick film

of oil b etween the bearing and journal will overcome

troubles due to overloaded j ournals .

W ith the modern automatic forc e - feed method of

lubrication,the oil

,in b eing forced through the top of

the box,i s ready to go to the servic e or pres sure s ide

of the j ournal whether the engine is backing or going

ahead,and does not have to r ide up the other s ide firs t

an d b e scraped off by the brass before i t has reached

the surfac e that most needs the lubricant .

For this reason driving box brass es may be fitted up

without side clearance and a tight fitting cellar may be

used to prevent any pinching ” of the j ournal . This

method gives the brass more crown bearing and allows

that much more side - wear before the j ournal is as loose

in th e brass as when driving boxes are fitt ed for grease

lubrication from the under side .

Excessive side clearance or pound between driving

j ournals and brass subj ects lo comotive machinery and

frames to severe dynamic stress es and this clearance

together with any looseness in the rods,requires the

piston to move a certain distance in taking up lost

motion before moving the engine . The volume of steam

used in this piston displac ement is a dead loss and in

the case of a modern 22 - inch consolidation engine with

29

1/J£ - inch tota l play in the boxes and 1/S - inch on each

crank pin,it amounts to about 225 lbs . of coal per hour .

A l l moving parts in a reciprocating engine should

be as devoid of lost motion as possible,for as soon as

there is lost motion,the stress to be resis t ed by the

pistons,rods

,crank - pins

,driving axles and frames

,is

changed from a static to a dynamic stres s,whose mag

n itu d e and effe cts (as was learned from draft gear

experiments% ar e extremely difficult to determine .

A lubricator does not operate p erfe ctly if it fails to

feed automatically in accordance with requirements of

the servic e,which is in proportion to speed and cut - off.

The automatic lubricator re l ieves the engineman of the

necessity of the care of it and allows him that time for

other d u t l es .

Concl u sions .

On e of the chief aims in modern transportation is

a safe reduction in ton m ile costs . A . very important

item entering into this is lo comotive efficiency , which

depends on a number of conditions , one of which is the

reduction of friction . This is accomplished by using

the best lubricant with the best method of applying it .

The automatic force feed system of lubrication does

not reduce the amount of oil actually needed but

does reduce the wast e of oil which accompanies other

methods . While the automatic force fe ed system r e

duces this waste,the principal benefit derived is a

more nearly constant coeffic ient of friction in the bear

ings lubricated . This is lower than the average of

the varying co efficient s of friction with any other

method .

30

Ad vantages Derived by the % se ofMcCor d System of

Force Feed Locomotive Lu b rication .

1 . Lubrication is pos itive .

2. Lubrication is proportional to valve travel and

therefore proportional to the work done by the loco

motive .

3. When lo comotive stops,lubri cation stops .

4 . Lubricator pumps against a pressure of more

than pounds .

r

o . No pressure in reservoir insures against leakage

and accidents to enginemen .

6. Reservoirs can be fill ed while in ful l operation .

7 . Each feed can b e adjusted separately .

Fe ed is adjustable from one drop in 10 strokes

to 20 drops in one stroke .

9 . Adjustment of feeds once made,they remain

accurate and adequate under all conditions .

10. A l l m oving parts ar e immersed in oil .

11 . Oil consu mption is red u ced and engine efficiency

is increased .

31

Directions for Operating theMccord Force FeedLubricator.

1 . There is no pressure in this lubricator,con s e

quently no steam to be turned off or no draining to

be done before filling .

2 . To fill,remove the filling cap and pour in the

oil after it has been heated sufficiently to pour freely

through the strainer at the filling hole . This may be

done either when the eng1n e 1s standing or running .

3. Do not fill this l u b r 1cator with oil drained from

hydros tati c lubricator,as it will contain water .

4 . Do not allow oil to fe ed out below gauge line .

5 . Th e feed is increased by screwing down the

knurled nuts on the top of the pump plungers,and is

decreased by screwing them up .

6. The lubricator body should be kept warm to the

touch so that the oil will remain thin enough that the

pumps may handle it easily . A heater chamber is pro

vid ed on the bottom of each lubricator into which a

small amount of steam can be admitted in cold weather .

7 . This lubricator operates automatically when the

engine is in motion,so there is nothing to turn on at

the b eginning of a run or to turn off at th e end of

a run .

8 . Should it b e necessary to give the engine more

oil than is obtained by the automati c mechanism,op

crate the hand crank on end of lubricator .

32

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valve is hot,as it is under this condition that the valve

should be tight . Be sure to clean the check valve and

seat thoroughly after grinding so that no smal l particles can get under the vagve seat and cause leak .

If the check valve is % tight,disconnect th e oil

pipe connection at the lubricator pump and turn the

hand crank % if oil shows at the pump discharge , the

pump is O . K. If the pump does not work,take it out

and make sure that the packing around the pump

plunger is tight,that there is no waste or other ma

ter ial coll e cted around the pump suction pipes,and

that all the ball che cks in the pump are in their properplac es .

Pump kerosene through the pump to wash and clean

the ball ch ecks and seats . The plunger packing should

be elastic enough that it will not be ne cessary to screw

the packing nuts down so tight as to bind u nn eces sar

ily on the plungers .

To determine if the oil pipe l eaks,conne ct a pressure

gauge on to the end of the oil pip e and operate the

lubricator by hand . The pipe line should hold a pres

sure of at least 300 lbs . without any variation on the

gauge . This is also an absolute te st that the ball checks

and th e packing in the pump are tight . If there is an

obstruction in the oil pipe,no oil will appear at the

end of the pipe after the lubricator has be en operated

by hand a reasonable l ength of time , and further , the

lubricator shaft will turn hard on the down stroke of

the plunger,and oil will leak ou t at the packing nut ,

and at the pump outlet connection .

4.

A fter doing work on any or al l of the oil pip es,

screw all union j oints tight and turn hand crank until

the oil pipes are fu ll of oil b efore the engine goes out .

This is important . The slightest leak in the whole sys

tem should be avoided,for it will materially affect the

regular del ivery of oil .

The feed is adj u sted by means of the knurled n u ts

on the top of the pump plunger . Screw these nuts

down to increase the feed and screw them up to de

crease the feed .

MCCORD AND COMPAN%

Peoples Gas Bldg . 50 Church Street

Chicago . New % ork .

35

BOOK IS D%B ON THE LA ST DATESTAMPED BELOW

AN INITIA L FINE OF 25 CENTSW ILL B E ASSESSED FO R FA IL% R E TO R ET% RNTHIS BO O K ON THE DATE D% E. THE PENALT%W ILL INC R EASE TO 5 0 C ENTS ON THE FO% RTHDA% AND TO ON THE SE% ENTH DA%

O% ERD% E.