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METHODS
-OF-
PROPELLING STREET CARS.
ENGINEER'S REPORT
—TO—
R. B. WOODWARD, Esq.,
President of the City Railroad.
»
SAN FRANCISCO, CAL.
WM. H. MILLIKEN,
Engineer.
1885. \ \
fTS.
y
I F" 70 5"
■ Ht
Engineering Office of W. H. Milliken,
22 California St.
R. B. Woodward, Esq.,
President City Rail Road Co.
Sir:—In accordance with your request, I here¬
with present to you my report in reference to the
proposal to change the City Rail Road from your,
present system of moving the cars by horse power, to
some other practical method of propulsion, with a view
of improving the service and producing more economi¬
cal results.
The City Rail Road has a present week-day ser¬
vice of 20 single horse cars on the Main line and 14
single horse cars on the branch line, with a varying
number of extra cars, both single and double horse, dur¬
ing commission hours and on Sundays. The length
of the road is 4*4 miles on Mission Street, from the
water front to 31st Street, and the short branch leav¬
ing the main line at 5th Street, passing to and down
Market and on Dupont as far as Sutter; thence down
Sutter to Market, gives an additional length of about
miles, making a total length of 5^4 m^es f°r
the entire line.
[ 2 ]
The number of horses provided for the service,
including those to take the place of extras, sick and
disabled animals is 285, and by a fair method of
calculation, I find the average expense per day of pro¬
viding the propelling power for your cars is some,
where about $11 for the double horse ,cars and $6.50
for the single horse cars — exclusive of the wages of
driver and conductor, but including the wages of hos¬
tlers, shoers, harness, cost of horses, general wear and
tear, and all items properly coming under the head
of "cost of the propelling power."
The grades on your line are not steep, those on
Mission Street being practically level, the heaviest
grade being on the blocks from 19th to 22nd Street,
each of these having a rise of 10 feet in 520 feet, or
1.92 per cent. On Dupont Street there is a short
grade, much heavier, of about 15 feet in 281, being
from Post to Sutter Street, or 5.3 per cent. PTom
these approximate figures, which are near enough
for the purpose of this report, I find that the amount
of actual effort used to haul your cars is excessively
disproportionate to what would be necessary if the
power was better applied, and the cost of maintaining
your animal power system is equally extravagant.
In arriving at a conclusion as to the best system
upon which to operate your road, in supplanting the
present horse power system, I have made very ex¬
haustive inquiries, availing myself of the experience
L 3 J
of others who have been engaged in a similar line of
o o
inquiry, as well as bringing to bear upon the subject,
that which has become, to me, a matter of personal
knowledge and experience. In this report I have
chosen to consider all the systems which, at this time,
command any attention from practical engineers and
railroad men, and I herewith place before you my
data and conclusion regarding each, only however,
with reference to the feasibility of their adoption
upon your line, or others upon which the same con¬
ditions occur.
The Cable System.
First in order I have considered the Wire Cable
system of propulsion, because here in San Francisco,
more prominence has been obtained for this system,
and greater perfection of construction and operation
has been achieved than belongs to all other systems
combined.
A Cable Railway was first constructed in this
city, to climb a hillside where horse power was totally
impracticable, the grade being 67 in 412*^ feet, or
over 16 per cent. The next road was the Sutter
Street road, which though previously operated by
horses, had a continuous heavy grade, averaging over
5 per cent. Then came the California Street road; the
Geary Street road; the Presidio road, and finally the
[ 4 ]
Haight and McAllister Street branches of the Market
street system, all of these roads having very heavy
grades upon which horse power would be practically
unavailable. For the beforementioned roads, the
Cable system is, undoubtedly, admirably adapted, and
certainly no system known would likely improve upon
the service.
Whilst the Cable system may be fairly granted
on all the above mentioned roads, a very great superi¬
ority over horse power and perhaps over any other
known systems, the question arises in your case,
where the road is practically level, whether the same
degree of comparative superiority would be main¬
tained.
Among the several conditions under which the
beforementioned roads are run, which vary from those
found in your case, the most important is the matter
of grades.
Your road, because of its level grades, has been
run with fair profit for years with horse power, and,
no doubt, may be run for years to come with even
greater profits as the travel increases from settlement
along the line. The horses having a comparatively
easy task in hauling the cars; the wear and tear on
the animals is less than is to be found on any other
horse power line in the city; your stock lasting longer
and doing a maximum duty in comparison with the
passenger haulage.
[ 5 ]
There are but two lines in this city which have
undergone the experience of being operated by both
horses and cables, viz: the Market Street main line
and the middle part of the Sutter Street line from
Market Street to Larkin. There are no means of
making any financial comparison between the two
systems on the Market Street line, because the
branch lines on McAllister Street and Haight Street
have always been run in connection with the main
Market Street line, and as these branches have been
operated as cable lines from their commencement, the
running expenses of the main line cannot be segrega¬
ted so as to arrive at a comparison with the expenses
under the horse power system. Still it is very gener-
allv admitted that on this line more economical results
✓
have been obtained.
As to the Sutter Street line, it was definitely as¬
certained in 1878 as between the horse power system
and the cable system, that the economical advantage
in favor of the latter was a saving of thirty per
cent, on the running expenses. In arriving at this
result, however, which is perhaps the most favorable
to the cable system that has ever been claimed, in
this city or is likely to occur again, there was an im¬
portant consideration overlooked, viz: that the road¬
bed being of such a cheap and perishable nature
would need to be replaced in a short time at more
than the original cost, so that much of the savings
I 6 ]
oil expenses would afterwards be swallowed up in
repairs. Besides this, the running gear, which was
of a cheap and inadequate design, had soon to be
discarded and replaced with more substantial machi¬
nery as the traffic of the road increased. The
experience gained on this particular road having
amply demonstrated the fact that cheap workmanship
and material will not answer the purposes of a busy
Railroad line using the cable system, all subsequently
built roads, including the extension of this road and
the extension of the original Clay Street road, have
adopted the plan of building the roadbed, under¬
ground tube, engines, running gear and general
plant, in a most substantial, thorough and workman¬
like manner of the best materials so as to ensure the
highest degree of lasting quality, this being found
absolutely necessary on the grounds of economy. As
there is no longer any inclination on the part of exper¬
ienced engineers to recommend the cheap and flimsy
constructions, having light forms of framework and
wooden sidings for the underground tubing, such as
was used in the original Clay Street Road and the
Sutter Street Road, and as the prevailing improved
practice is to build substantial work on good founda¬
tions and first-class machinery throughout, I feel that
it would be a sacrifice of good business principles and
a gross error of judgment for your company to adopt
any but the best and most improved form of plant,
[ 7 ]
should you finally decide to change your road to the
cable system.
There are two forms of underground tubing for
cable roads, which have given satisfactory results in
this city. The first is exemplified in the case of the
Presidio Road where the frame work is of heavy cast
iron ribs, set closely together and connected with a
sheet iron conduit dipped in asphaltum, the other form
being exemplified in the Market Street system, the
Clay Street extension, the Sutter Street extension and
the California Street road, the tubes in these roads
being a combination of iron frame work and concrete
conduit. Which of these forms of construction it
would be better for your company to use, in the event
¥
of your adopting the cable system, it would be prema¬
ture for me, at this time, to suggest. But for the
purpose of this report, it will suffice for me to say that
when the matter of adopting a form of tubing needs
to be definitely decided upon, I would recommend
for your consideration the Presidio Rail Road plan,
the Market Street plan, the plan of John D.
Isaacs consisting of a concrete conduit without the
expensive iron frame work, but in which the slot,
irons and carrying sheaves etc. are anchored in a
peculiar but effective way, and certain plans of Messrs
Low and Grimm who have several meritorious designs
for cable road tubing, which should be considered
with the rest in making a final selection. As to the
[ 8 ]
form of Engine house plant, no recommendation need
be made here, further than to suggest that your com¬
pany should be careful to procure the very best
design, with a view of securing a maximum useful
effect and minimum risk of disarrangement.
Assuming that your company would desire, if at
all, to build a cable road in a thoroughly substantial
manner, I have made some inquiries from different
sources as to what the estimated cost would be of a
first-class equipment; also 1 have personally made my
✓
own estimates. These I have averaged, giving the
result that to .change your road from the horse power
system to the cable system, and to provide 34 new
cars, would cost your company $450,000. This not
including any change on your branch line, which would
remain as it is.
The estimate is larger than you may have expec¬
ted, but as it will be necessary to provide a pile
foundation on the made ground on Mission Street,
below Main to the water front, if concrete tubing is
used; and as a very expensive curve must be con¬
structed from 11th to 14th Street, it will be found the
estimate is reasonable, though not intended to be
accurate.
The advantages of the cable over the horse
power system must be well known to your company,
they having long since been thoroughly demonstrated
in this city under its observation. I will refer to
[ 9 ]
this report simply to aid you to draw a comparison
with other systems.
ist. This system has largely decreased the run¬
ning expenses as compared with the horse power
system, and is more profitable to operate.
2nd. It is more satisfactory to the traveling
public and receives a greater amount of patronage.
»
3rd. It is more satisfactory to residents along
the line and encourages the property interests, thus
indirectly building up the interests of the road.
4. The running expenses being practically fixed
and unvarying, the cost of labor and fuel not materi¬
ally changing throughout the year, whilst the cost of
horse feed is often greatly increased, the comparison
between the two systems as a steady investment for
*
capital, is in favor of the cable system.
The minor merits of the cable system, which
concern the facility of its operation, cleanliness, nois-
lessness, great capacity for accommodating traffic,
etc., need not be elaborately referred to, as these
are points included under the more comprehensive
heads above. There are some acknowledged dis¬
advantages in the cable system, which must be con¬
sidered in arriving at a conclusion as to its availability
in your case.
1 st. The system is an expensive one, and it will
therefore be necessary to closely calculate before its
[ IO ]
adoption whether the saving it effects in running ex¬
penses and the increased revenue it will bring from
prospective new travel will overbalance the interest
account of the new capital which will require to be
invested. In your case you will need to save on
expenses or add to your traffic, either or both, to the
extent of about $ioo per day, to make the change
desirable, in a financial point of view.
2nd. There is always a liability for the entire line
to become temporarily disabled, owing to the breaking
of the cable or disarrangement of the machinery in
the Engine house. The loss of earnings from these
o o
stoppages in this city I have not accurately ascer¬
tained, but they have, at times, been very great.
3rd. There are but two ways of operating
branch lines. Either the branch shall have a sepa¬
rate cable and winding machinery from the main line,
or a single rope may run both. When the branch line
occurs a distance from the Engine house, and it has a
separate cable, this cable will have to extend beyond
its serviceable length. In your case as a branch line
commences at Fifth Street, a distance of nearly one
mile and a half from where the Engine house would
be located, viz: on the company's lot at 14th Street, it
follows that you would have to operate nearly three
miles of cable and provide the usual carrying pullies
for its support, beyond the point of junction with the
main line, unless you re-locate your Engine house at or
[ II ]
near the junction, upon a lot to be obtained for that,
purpose. If a single rope be used for both branch
and main line, then you would have to operate a very
long cable having a total length of nearly 34,000 feet
from the Engine house down town, using another cable
from the Engine house out.
4th. There is no economizing the power used
on cable lines responsive to the reduction of travel oc¬
curring on your lines during certain hours of the day.
In other words, there is no constant proportion be¬
tween the power used and the traffic. The cable must
always be moved, though but one empty car is at¬
tached, and as the moving of the cable consumes most
of the power at all times, it follows that the withdraw¬
al of a few cars or their being run empty does not
make any appreciable difference in the amount of
power used. Mr. Hanscom in his admirable paper
read before the Technical Society of the Pacific Coast,
gives the power required to move the cable as averag¬
ing 68 per cent., whilst but 28 per cent, is required to
move the cars, and 4 per cent, to move the passen¬
gers. It follows, therefore, that 68 per cent, being a
constant factor, the only possible saving of power may
be a small amount due to a lighter car or passenger
haulage, or both, this never to exceed a few per cent.,
though the traffic be nearly suspended. In running a
few late or all night cars, it would be economy to dis¬
pense with the Cable haulage entirely, and provide for
[ 12 ]
horse haulage in the late service. This is done in
Chicago, where the cable is stopped at 12 o'clock, p. m.
and until five the next morning a few cars are run
with horses. This matter should be considered in
providing for detachable grips.
5th. There is a difficulty in adopting the cable
system on your branch line, which runs on Sutter
Street, viz: there is already a cable line on that street,
and as your cars run over its track, you would there¬
fore be compelled to either use its cable and adapt your
entire system to that short piece of road, for two inde¬
pendent cable plants cannot be placed in the middle of
a narrow street, or you would have to change the route
to some unoccupied street. It would of course never
be entirely satisfactory for two Railway Companies to
nse the same cable, and it is very doubtful if any
such arrangement could be effected.
6th.. The cable system has not yet been tested
on lines having frequent curves such as occur on your
branch line, which passing from Mission Street to
turn into Filth, into Market, into Dupont, into Sutter
Street—these being right angle curves. There is a
general impression that the cable will prove unsatis¬
factory on roads of this class.
Electric Roads.
Several experiments have been made recently^
and others are proposed, with a view of adapting elec-
[ l3 ]
tricity to Street Railway Car propulsion. The success
which a few enterprises in this line have met with,
have induced many practical men throughout the
country to at least hope for, if they have not complete
faith in the final establishment of this power as the
most available for street railway purposes.
On your behalf I have examined the matter very
thoroughly, and in a general way, will here lay before
you the points pro. and con. which have developed
themselves to me in the course of my inquiries.
rst. As regards the cost of these roads I have
O
found that no electric system has yet been practically
developed, which promises cheapness of construction.
The use of an overhead conductor involves so many
difficulties, that it is no longer accepted as feasible for
surface roads. The storage battery plan, where no
conductor is needed, has been found inadequate, and
the only really promising projects are those which have
conductors located underground, for surface roads, and
above the surface for elevated roads. It is scarcelv
j
necessary to consider the relative cost of all the pro¬
posed systems, as but one, that having the underground
conduct:;!", offers to be practical on your line. This
plan I will consider as to its cost and. general avail¬
ability .
The underground conductor of necessity requires
an underground tube, a tube not unlike that required
in die cable system, though perhaps a trifie smaller. As
[ 14 ]
this tube will be subject to all the conditions and re¬
quirements attending the use of the cable tube, especi¬
ally as to its supporting ordinary street traffic, it will
need to be equally strong and of quite an expensive
construction; any attempt to lay down a cheaply con¬
structed tube would be poor economy. The matter of
insulating the conductor will prove a difficult problem
to solve, and constant care will need to be exercised
to preserve it. The rolling stock will need to be new,
and more expensive, probably, than that of the cable
system, whilst but very little difference in cost of
Engine house plant can be expected, for although elec¬
tric motors and appliances do not involve very expen¬
sive or complicated mechanical work, still their cost is
greatly increased by some very heavy royalty charges.
Whilst I am at present unable to state what the
actual cost of an electric plant would be to properly
serve the requirements of your road, I can say posi¬
tively that it will vary but little from the cost of the
cable system, as each requires an underground tube,
continuous conductor, (cable or rod) expensive engine
house plant, and special motors or rolling stock. The
electric conductor, however, will likely last longer than
a cable, and will not need to be duplicated to provide
for emergencies.
The running expenses of this sy stem will certainly
not be less than with cables, and future experience may
show that the expense of operating and maintaining
[ 15 ]
will be greater than in any proposed mechanical sys¬
tem of operating street railroads now before the public.
The amount of useful effect which can be obtained
from electricity is at present unknown. It has been
demonstrated that a high per centage of useful effect
may be obtained in using electricity as a motive power
under favorable conditions, but as no street railroad
with numerous independently moving cars has yet
been operated by electricity, the per centage of useful
effect which can be obtained under these conditions
has not been demonstrated.
It has lately been widely published that on the
Port Rush road in Ireland, the useful effect of the elec¬
tric current was so small at a distance of two miles from
the generating machine, that steam power had to be
substituted. The amount of coal consumed in produc¬
ing the electricity, and the power of the generating
dynamos will be in inverse proportion to the useful
effect it produces; the greater the useful effect, the less
the required power of the generating machines, and
the less coal will be consumed, and vice versa. There
cannot possibly be a useful effect greater than that
obtained in the cable system, viz: averaging 32% ac¬
cording to Hanscom's figures, because the moving of
the generating dynamos will of itself consume 20% of
the engine power; the dynamos on the motors another
20%, and 18% is not an excessive allowance for leakage;
this would leave a balance of 32% of available car
[ .6 ]'
moving force—any more liberal allowance would simply
lead to disappointment. A disadvantage belongs to
the electric system relating to the speed with which
the d) namos on the cars are run; as the ordinary speed
of a street car wheel is about 80 revolutions per min¬
ute, and as it is necessary to run the dynamos about
1200 revolutions, there is required a system of speed
reducing gears to transmit the motion from the dynamo
to the car wheels. These gears make a great noise,
and render it uncomfortable for passengers to ride near
them. This difficulty was found to be very pronounced
in the experimental cars lately run on the Garden Street
linewn Cleveland, Ohio; the noise from the transmit¬
ting gears was' so great, that it was difficult to hear
o o o '
the loudest conversation within the car. How far the
naked conducting rod within the underground tube,
heavily charged with electricity would prove objection¬
able, cannot well be determined; the electric light wires
have to be covered with an insulating material as a
matter of safety to life and propert); whether the un¬
derground naked conductor, always accessible to the
curious and ignorant, through the slot in which the
shank of the grip passes would be found too danger¬
ous to be permitted by the city authorities, is a matter
which you would require to consider in deciding upon
the availability of this system.
The electric system is certainly one that offers
great facility in the matter of manipulating the car, and
[ '7 ]
the system is free from most of the objections urged
against the employment of mechanical motors, but it is
not established that a reasonably profitable useful effect
can be obtained.
This system will not be available on your branch
line on Sutter Street, for the same reason that the
cable system is unavailable there, viz: because that
j '
street is now occupied with the underground tube of a
Cable Railroad.
Of the several electric roads now running, none
operate under the conditions of your case, so that
should your Company adopt this system, it would be
purely an experiment without precedent anywhere, and
no satisfactory deductions could be made as to its
availability, until you had built and equipped your
road thoroughly and completely.
The cost of an Electric plant for your main line
1 estimate would be, including a concrete underground
conduit, about $375,000.
Steam Motors.
It is scarcely necessary to consider the availability
of motors of this class, for the city ordinances would
be found prohibitory at the outset. They are, how¬
ever, unavailable for the following reasons:
They are expensive, and because of their having
to carry both water and fuel, they would have in your
case a very small per centage of useful effect, as most
[ i8 ]
of their power would be expended in moving their own
weight. They would need skillful engineers to handle
them. They would be very uncleanly, and if coal was
used for fuel, they would be a positive nuisance on ac¬
count of smoke and fumes. Should petroleum be used
for fuel, there would be little or no smoke escape
from their furnaces, but disagreeable fumes would still
be emitted, and there could be no hope of inducing the
general public to accept them at their best. There is
much danger in using them in crowded streets, and
they would be found unavailable in your case because
the traffic is not sufficient during a portion of the day
to give profitable employment to separate locomotives
for each car run. To accommodate passengers on the
motor, in proximity to the boiler and machinery, would
be impracticable, on account of the disagreeable odor,
heat and vapors which it would be difficult to entirely
prevent.
Motors of this class being bulky and of great
weight, their use would necessitate a change in your
present road-bed, which would be found too light to
sustain them.
Steam motors are now operated on the Park
branch of the Geary Street Cable Railway, but they
are not used to haul single cars, but trains of three cars
at a time generally well filled with passengers, and
even in this service they are found unsatisfactory, have
been loudly complained of, and are to be withdrawn at
[ !9 ]
an early day. The steam motors in use in the City of
Sydney are about to be withdrawn, but in London,
England, they are again being used, although a promi¬
nent engineering firm whose letter is before me, writes:
" We are of opinion that steam for tramway pur-
" poses is bound to go out from what we have seen
" and our own experience."
Coal Gas Motors.
Motors to be supplied with receivers filled with
coal gas have been suggested for Street Railway pur¬
poses, but they have not yet obtained recognition as
practical devices. They would, if otherwise found
available, have some serious defects, among these are
to be enumerated the objection that coal gas engines
have no reversable motion like ordinary engines, and
reversing gears or similar devices would be necessary,
which would render the machine too complicated, and
totally unfit for the rough work of a street car line.
The gas engine is an unmanageable affair as to stop¬
ping and starting, and would need to be kept con¬
stantly running independent of the car motion, thus
introducing more complication of mechanical parts
liable to disarrangement. They would have no recuper¬
ative power; being charged to make the round trip ; if
the power gave out, the motor would be powerless to
move. They would be expensive to construct, main¬
tain and operate, and inasmuch as you would have to
[ 20 ]
compress the gas so as to conveniently store it on the
motors, it seems the better plan would be to compress
atmospheric air, use it expansively and save the price
of the gas, which would either have to be purchased
from the Gas Company or made with a special plant.
Some experiments have been made by Messrs.
Danks & Barnes, near Melbourne, Australia, of which
I find a very intelligent account in a Sydney paper.
The data obtained from this trial is interesting, and is
\
contained in the following extract from the report of
an experimental trip.
" The experimental tramcar which was sent on its travels on
May 21, between Clifton Hill and Alphington, weighs about two
tons, and is driven by an ordinary 3A-horse power gas engine.
Twenty people rode on the car, bringing the weight up to over
four tons, and rode to Alphington and back, 473 miles, which was
done in 31 minutes, equal to 9 A miles per hour, which is beyond
the average speed allowed in the city—seven miles per hour.
' When the car started, the indicator showed 66lbs., which was
reduced to 32lbs. on returning; giving a consumption of 9 cubic
feet of gas per mile, or a cost for the \2/z miles run, carrying four
tons, of 2pid."
From the data given in the above item, it is a
simple calculation to find how much it would cost to
supply the gas which cars for ) our line would require.
Taking gas at two dollars per thousand cubic feet, the
present price in this city, it would cost in the neighbor¬
hood of $4 per car, per day, for gas alone, leaving out of
the calculation the cost of compressing it, which would
be at least a dollar more. Not only would the expense
[ 21 ]
of supplying and compressing the gas in your case
render this system unavailable, but the mechanical
complication of the parts of the motor would of itself
militate against the success of the system.
The High Pressure Compressed Air System.
Motors operated by compressed air are not yet so
widely introduced as to be entitled to acceptance as
proven mechanical and financial successes, and beyond
criticism as to their merits. Still we have sufficient
demonstration to show that thev are available in some
j
cases and their defects have been made so apparent as
to no longer need practical tests and trials to discover
them. There are several roads now in operation under
this system, the one at Nantes, France, giving most
excellent satisfaction.
Other roads however, as for instance, the one run
for a considerable period on the Gavon road, Glasgow,
Scotland, and one in Paris, have been abandoned,
whilst the New York Pneumatic Railway Company,
although it has expended a very large sum in experi¬
menting, has not ) et succeeded in inducing the Rail¬
way Companies to adopt their system. At Nantes,
the Mekarski system is used, which consists of a motor
supplied with several cylindrical receivers for storing
the air at the high pressure of 450 pounds per square
inch, the receivers being charged at one end of the
1
[ 22 ]
route, to carry the motors to the other end and back,
a distance of 7 miles. The machines are very large
and heavy and carry over 6o passengers seated, un¬
loaded they weigh about 20,000 lbs., and the trips are
made at long intervals. The service is very sat¬
isfactory, as the conditions under which the line is
operated are favorable, whilst the general public and
householders along the line desire its continuance.
The Beaumont machine has long engaged pub¬
lic attention in London, England, and elsewhere, and
has received favorable criticism. Like the Mekarski
machine it is heavy, weighing over ten tons without
load. It has been operated with the enormous pres¬
sure of 1000 lbs. per square inch; this machine is not
in use at present, except experimentally. The Scott-
Moncrieff motor of London, England, was a lighter
' O ' o
machine; weighing not over 17,000 lbs. unloaded, with
a carrying capacity of 40 passengers, using air at a
pressure of 400 lbs. per square inch.
All these motors being charged with a pressure
impracticable as a working pressure, a reduction is
made to about 100 lbs. before the air is admitted to
the working cylinder, so that a loss of part of the en-
ergy, due to compressing the air from its working
pressure to its highest storage pressure, occurs at the
outset. Another loss occurs with these machines due
to the necessity of cooling the air, which rises in tem¬
perature as it is being compressed, though the Beau-
/
[ 23 ]
mont and Mekarski motors attempt to avoid much of
this loss by reheating the air before using it in the
working cylinders.
The "Hardie" motor, one of the best, most mod¬
ern and improved, stores 110 cubic feet of air at a
pressure of about 450 lbs. per square inch and works
the air at 100 lbs. This machine has attracted much
attention in New York, and it may be adopted perma¬
nently on a street railway near that city, at an early
day, negotiations to that end being now in progress.
The objections against the before named machines
affecting their adaptability to the conditions on your
line, may be enumerated as follows:
1 st. They all require to store the air at a very
high and work it at a low pressure, this involving a
loss of useful energy.
2nd. They all require to have a greater storage
capacity than is practicable on small light cars, such as
your company requires, thus the tendency of the sys¬
tem is towards bulky machines, which are originally
too costly and afterwards too expensive to operate and
maintain.
3rd. There being no recuperative power in these
motors, their effectiveness can only be secured by con¬
structing them so as to provide for the maximum
contingencies of their service, whilst they would or¬
dinarily only be required to operate under the
minimum conditions. That is to say whilst they must
r 24 j
he made capable of hauling from end to end of the
route and hack, the heaviest probable load, and make
the most frequent stoppages, when the track is in the
worst condition, yet their ordinary service would he to
haul small loads under favorable conditions. Thus
there is constantly provided more effectiveness than is
used, to the great sacrifice of economy.
4th. These motors being of necessity heavy and
cumbersome, your present track would be found too
light to sustain them, and a new road-bed and track
throughout would be necessarv.
o j
5th. The use of high pressure air involves the
use of several machines to compress it, the friction of
which machines largely consuming the power of the
prime mover, i. e., the steam engine, there follows a
large per centage of loss of useful effect.
Pardy's Low Pressure Compressed Air System.
This system proposed by Mr. George Pardy,
consists in employing a number of light weight motors,
supplied with receivers to contain about 5d cubic
feet of air at about 100 lbs. pressure per square inch.
These receivers are placed 011 the car either on the
sides over head, or under the seats; in either position
owing to their small dimensions, they are not unsightly.
Ordinary locomotive engine cylinders are carried un-
t
der the floor of the car and connections are made
["2.5 ]
directly with the car axles or wheels. There is an
underground pipe placed between the up and the
down track, four to six inches diameter, running the
entire length of the line. At every 500 ft. a branch
from this pipe leads to the center of each track, these
branches terminating in a peculiar form of valved out¬
let, having 2^ inch diameter opening at the street
surface.
The street openings are left uncovered, but any
dust, dirt, water, etc. which passes into them is caught
in a receptacle, to be removed periodically, or it may
pass into the adjacent sewer. There is a flexible* noz¬
zle carried on the car connected with the receivers,
which nozzle the engineer pushes down into these
street openings to open the valved outlets and form air
tight connections with the receivers, whenever he
desires to replenish them. The operation of replenish¬
ing requires about six seconds, and takes place during
the ordinary stops the car makes to pick up or let
down passengers.
The underground pipes are kept constantly filled
by compressing machinery located anywhere near
the route, and shut off valves are placed at intervals,
so that short sections of the pipe may be temporarily
closed for repairs, when leaks are discovered. The
car is provided with a long slotted opening in its floor
or platform where the engineer stands, through which
slot the nozzle is inserted into the street opening, so
26 ]
that if the car stops anywhere within seven feet of the
opening, the engineer has full access to it. The entire
details of the system have been thoroughly planned,
and all the exacting requirements of street railway ser¬
vice, respecting reliability, speed and convenience of
operation have been, as far as I can judge, admirably
provided for, in a simple and practical way.
Some partial tests have been made with the
system by the Risdon Iron and Locomotive Works
of this city, which experiments, though successful and
fully demonstrating that a low pressure of air and small
storage capacity on the motors is feasible and economi¬
cal, have not yet been completed and have been
temporarily suspended owing, as I am informed, to
the desire on the part of the Risdon Iron Works,
who have the assignments of the Pardv Patents for
O J
this city, to first obtain assurances from the Railway
Companies here, of their intention to adopt the system
upon final demonstrating its success, before they un¬
dertake the great expense of constructing an entire
working line. So far the companies interested have
not given this assurance and negotiations to bring
about an understanding on this point, have been de¬
layed awaiting results of the experiments with the
electric system on the New York Elevated roads.
The Pardy system is an improvement upon the
high pressure systems in the following very important
particulars:
[ 27 ]
1st. As it is operated with a low air pressure not
exceeding ioolbs. per square inch, the air may be com¬
pressed at one operation in a single machine, instead
of progressively in several, as in the high pressure
systems, thus saving the original cost of, and power
necessary to run these additional machines; also at this
low pressure the proportional useful effect is much
greater.
2nd. It permits the adoption of light weight
motors, having small air receivers not exceeding fifty
cubical feet in their combined contents, so that your
present roadbed and track will amply sustain them,
and the power required to move them will be much
less.
3rd. It permits the replenishment of the air to
recuperate the power of the motors at any point 011 the
line, so that at every starting the motor may exert its
maximum power.
4th. In its adoption the system involves less
expenditure of capital in providing motors and com¬
pressing machinery, and avoids the cost of replacing
\our present roadbed.
5th. It would be less of an experiment mechanic¬
ally and financially, offering no risk whatever in its
adoption.
6th. It permits the application of the machinery
and motive power upon your present form of car, with¬
out encroaching upon the space reserved for passengers.
»
[ 28 ]
It improves upon tbe cable system in the follow¬
ing points :
ist. It can be put in operation on your line at
about one fourth the cost.
2nd. It can be operated at about 30% less ex¬
pense.
3rd. It is never liable to get out of order to such
an extent as to suspend traffic.
4th. A better schedule time may be made and at
least one car on your main line dispensed with, without
interfering with the service.
5th. It may be operated on your branch line on
Sutter Street and on any future branches running on
streets already having cable lines.
6th. It can be put into operation without inter¬
fering with your present traffic or disturbing your
roadbed.
7th. It involves no financial experiment, as its
daily running expenses, including interest on new cap¬
ital invested in applying the system will not increase
your present expenses but will rather materially
decrease them.
It is better than the electric system—
1 st. Because it will not cost over one-third the
money to put it into use.
[ 29 ]
2nd. The daily expenses will be about 20% less,
including interest on capital invested.
3rd. There will be no disturbance of your pres¬
ent road-bed.
4th. It will not be affected by storm water
which in the electric system, will at times flood the un¬
derground tube and destroy insulation, and suspend
the operation of the whole line.
Systems Compared.
The purposes of this report do not require a close
technical criticism of the different systems referred to,
and it may be assumed that all are practical in a
mechanical sense; but whilst allowing the highest
claims of merit made by the advocates of each to pass
»
undisputed, they will now be compared purely from a
financial point of view.
The following table exhibits what is offered as
an approximate estimate of the cost of construct¬
ing and operating each system, exclusive of such
items as taxes, licenses, engine house or stable rent,
drivers and officers salaries, etc., for these items being
common to all systems, they may be omitted without
impairing the accuracy of the comparison.
[ 3° ]
•#
COMPARATIVE TABLE,
Showing Cost of Providing and Operating
Various Systems.
SYSTEM.
MAIN
LINE.
BRANCH LINE.
Cost of Providing
Daily Expenses
Cost of Providing
Daily Expenses
*Horse Power...
$50,000
$150 OO
$21,250
$63 75
Cable
4505000
203 OO
NOT AVA
i
ILABLE
Electric
375>000
165 OO
1
NOT AVA
ILABLE
Coal Gas
130,000
200 OO
45,OOO
120 OO
High Press're Air
175,000
164 OO
66,000
j
55 00
Low Pressure Air
105,000
125 OO
1
40,000
53 00.
*The horse power system provides for bobtail cars with only a driver; all the other systems
provide for cars of double the capacity, with a driver and conductor.
I do not burden this report with detailed calcula¬
tions, but will explain that 1 have charged the horse
power system in the above table with about 200 horses
for the main line at 8oc. each, per day, to cover feeding,
shoeing, grooming and wear and tear of animals, with
an item for wear and tear of cars and interest on capi¬
tal used in providing animals and rolling stock. The
branch line being charged with 85 horses and other
items in proportion.
The running expense account of the cable system
is charged (for the main line only) with coal and water,
two engineers, two firemen, twenty conductors, which
[ 3i ]
would be a new expense not incurred with your pres¬
ent bob tail cars, wear and tear of machinerv and
' j
cable, interest on new capital at 6% per annum and an
item for sundries.
All the other systems are charged with analogous
items according to the requirements of each case.
The estimated cost of the construction of the dif¬
ferent systems is based upon the assumption that each
will be provided with 34 motors and necessary machin¬
ery to run them on the main line and 14 on the
branch line.
Recommendation.
Your present horse power system with its small
single horse cars, having driver and fare box but no
conductor, is evidently not satisfactory, and in conse¬
quence of there being already a competing cable ser¬
vice on the next parallel street on one side, with the
prospects of another soon to be established on the
other side, there is a danger that some of your traffic
will be diverted to these competing lines, unless your
service is improved.
Of course it would be folly to spend more money
in improvements than } ou can reasonably expect to be
returned in the shape of profits from increased trade,
and you will desire to avoid any unnecessary risks in a
financial sense.
It is also desirable that your company should not
enter into any expensive mechanical experiments for
[ 32 ]
the purpose of demonstrating the impracticability of
some visionary scheme, and it is with a thorough
appreciation of the views expressed by yourself and
the Directors of your Company in this respect, that I
offer my final recommendation.
The cable system will not suit the conditions of
your case, because of the great expense attending its
adoption, and although mechanically considered it
would prove very satisfactory, if properly laid down,
there is too much risk of your being able to increase
your traffic, with competing lines so close on either
side, as to be remunerated for the outlay.
The electric system being both expensive and
undeveloped, would be experimental, both in a financial
and mechanical sense, with, I am convinced, a posi¬
tive certainty of its proving unsatisfactory.
The only system that I feel warranted in accept¬
ing is the Pardy Low Pressure Air System, which is
at once the cheapest, and promises to be the best for
your purpose; and inasmuch as the Risdon Iron Works
- Company offer, under certain reasonable conditions, to
put this system into practice on any suitable line at
their own risk, terms can be made which will com¬
pletely relieve your Company of all consequences of
mechanical failure.
There is no reasonable doubt, however, as to the
success of the Pardy system, for there are precedents
which demonstrate all the points involved.
[ 33 ]
The Nantes Railway, the line on the Gavon road,
Glasgow, the Hardie Motor in New York and the
numerous other instances of the use of compressed air
for street railways, give a positive assurance that
this power when properly used is available for the pur¬
pose.
The underground pipe can undoubtedly be kept
tight at the joints, for there is a precedent in the
eight miles of much larger pipe conveying air to the
drilling machines in the Mont Cenis tunnel without
any loss from leakage, whilst a company in Birming¬
ham, England, is now engaged placing air pipes
underground to supply motive power to a large portion
of the town, some pipes being as large as 36m. diam.
The facility with which the receivers on the car
can be replenished has been demonstrated by actual
test, and it has been found that an average of five sec¬
onds is required to re-fill them, depending upon the
amount required.
The underground valves are perfectly protected
from dust and dirt and are isolated from any influence
which frost might have, neither ice, snow, street wash¬
ings or storm water can possibly affect them, whilst
the contingency of any valve getting leaky or out of
order in any way, would have no other effect than to
require the engineer on the motor to proceed to the
next valve 500ft. distant, whilst the leaky valve could
be replaced in a few minutes.
[ 34 J
The reduction in the weitrht and bulkiness of the
o
motors give assunmce that less air will be used in
moving them, that they will be easier to handle than
those heretofore used, and that your present roadbed
will sustain them.
The facility with which these motors can be
stopped and started, cannot be doubted, for they will
be provided with air brakes, and they will be started
with the same speed as locomotive steam engines, but
without the suddenness of the Cable system.
The use of the low pressure avoids the objection
that the system would be dangerous in crowded streets.
The useful effect will of course depend to a large
extent upon the design of the motors, and the quality
of the workmanship employed in their construction, as
well as the design and construction of the compressing
Machinery. There ought to be realized fully 50%
especially when it is considered that on your line much
of the travel is down grade, where no air would be used
to keep the car moving. The fuel account will cer¬
tainly be less than with any system proposed.
It is true the system does not permit the ascension
of extreme grades, all grades can be overcome, how¬
ever, on your line, and even steeper ones, for inasmuch
as the passengers are carried on the motor and add by
their weight to the adhesion to the track, there can be
no doubt these motors may easily ascend any grade
[ 35 ]
upon which they could be held by the brakes from
rolling back.
For intermittent short, steep, grades upon other¬
wise level roads, an underground endless cable worked
by a fowler clip pulley, revolved by an engine supplied
with air from the pipe main may be advantageously
employed. The ascending motor could be easily
hooked on to the moving rope through a slot in the
street surface, similarly as is now done in the cable
system, the hook or grip being taken up at the top of
the grade.
As the Pardy system involves no radically new
ideas which one might hesitate to indorse, but as every
proposition connected with it, is a plain matter for cal¬
culation, based upon established data, and as I have
closely examined these and found no reasonable prob¬
ability of the system failing to give satisfaction, and as
it is the cheapest system proposed, I unhesitatingly
recommend your company to adopt it in preference to
all others herein mentioned.
Respectfully submitted,
W. H. MILLIKEN.