The sun., 1897-05-06

possible only In consequence Of the short
headway Of one minute, and this headwsy
IL possible only by reason of the low aver
age speed Of the local trains, which is about
ten miles per hour. A higher rate Of speed
would necessitate increased headway and
reduce the capacity of the road.
The Engineering Magazine Of July, 1892,
contains n very practical article on this
subject by LOUIS HEnPRIN, in which he
shows that II, with a maximum speed Of
| twenty miles per hour, there can be head.
way Of one minute and capacity Of, say,
$1,000 seats per hour, an increase to forty
miles per hour would, to secure equal safe
~, require a headway OF two and half
minutes, and reduce the capacity of the line
to 5000. The reader is referred to this
magazine article for full explanation Of
this apparent paradox
1t has been suggested that increased
capacity can be secured by doubling the
weight Of the engines and the number Of
cars In the train. This Is a mistake. The
present elevated structures would not bear
engines heavier than those now In use, and,
II stronger structures were provided, the
time required for heavy trains to stop and
start would 10 increase the headway that
the advantage Of an increased number of
cars would be lost.
That heavy engines and long trains will
not increase the capacity beyond that Of
the present Manhattan Elevated line can be
abundnntly proved from the experience of
other roads In Europe and the United States.
The Metropolitan tunnel line in London
runs trains OF six cars at ten-minute inter
walls, both on the inner and outer circles.
1t has thus six trains per hour, using a
steam locomotive OF 94,OsO pounds, or
double the weight of the Manhattan en-
gines. 1t has 216 full seats to train, and
its capacity per hour is only 1,296 seats.
II 1t were possible to reduce the interval
with safety to one-third, which is as much
as could be expected upon the New York
tunnel line, the capacity would then be
only 1888 seats per hour, or one-fourth Of
that Of the Manhattan Elevated.
Take another example: the Boston and
Maine Railway Company year ago ran
train to Reading from Boston. twelve and
three-quarter miles, using an engine weigh.
ing 6e,4so pounds. There were six cars
and 37s seats In the train. The speed was
21.25 miles per hour. To satisfy a public
was provided, but, although stops were
only once in two miles, the heavier engine
could not make schedule speed. Then the
old engine was restored and an additional
car added to the train, but the train was
too heavy to stop and start quickly, and
the additional car was taken of. II this
train had been run at three minute inter
val, which is, in the opinion Of Mr.. j. V.
MEIGs, the shortest possible for an engine
Of this weight. the hour capacity would
have been 7 500 seats.
There is four-track visduct steam road
crossing and encircling Berlin, similar in
character to the proposed New York system,
using an engine weighing 92,594 pounds,
capable Of pulling the maximum train of
ten cars with 500 seats, weighing, loaded,
211 tons, or nearly double the weight Of our
elevated trains. They are sent out at inter
walls of five minutes, and their capacity is
5000 seats per hour. Hany one of the trunk
lines running from New York city should
despatch full trains of ten cars, carrying 600
passengers each, at intervals of ten minutes,
which would be an unusual volume of bust.
ness, it would carry but $500 per hour, or
only one-fourth as many as the Third
Avenue Elevated.
These illustrations may suffice to show
how far the Manhattan Elevated is In ad-
vance of other lines in its capacity for pub
lie accommodation; and that heavy engines
and heavy trains, requiring increased head
way between trains, will not increase, but
rather diminish, the carrying capacity per
hour. They also raise the question whether
the excessive expenditure required for the
construction Of the proposed tunnel line, in
cluding 50 many elements of danger and
uncertainty, can be considered as warranted
by the increased capacity thereby secured,
and wheti. r a greater capacity and far bet
ter and more acceptable accommodations
cannot be secured by some modification and
extension of the elevated system, aided by
independent mechanical motors upon the
surface lines.
In the further consideration of this sub
ject, 1t is necessary to inquire what are the
prospective demands for transportation in
the future. Mr.. HEILPRIS in the article to
which reference has been made, states that
no system of rapid transit ought to be
deemed sufficient to meet the demands of
the immediate future in New York that
does not offer transporting capacity, com.
bining speed with comfort, of about 15O,-
900 passengers in one direction per hour.
President VREELAND of the Metropolitan
Company in this city has stated in
published interview that the Broadway
line carried 10000, 900 passengers and
3O,OOO,O0O transfers. or 10000, 900 in
all, per annum, and he thought that all
the surface and elevated roads carried
100000 passengers, and that the
natural annual increase was 100000.
From these data the daily average would
be about ], 300, 900, with uniform distribu-
ton; but the maximum for which provision
must be made should be much greater.
At this present writing, statistics of the
various elevated and surface lines are not
available for the determination of the prob
able number of rapid transit passengers to
be provided for at the busy hours of the
day; and the numbers are not equal on each
of the four elevated lines. 1t was stated in
1894 that, while the Third avenue line