New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1904-06-06
TUNNEL ROADS IN LOYDOu

The recent initiation of service on the fourth
underground electric road in London lends n
writer in The Engineering Magazine" for June
10 lndlcate some of the differences between
them. Tho chief one is in the diameters Of the
tunnels. None Of the older tubes" measure
more than Twelve feet across and the first lot
10 De opened were still smaller. Three others.
now in process of construction, will be \ trjfIe
larger but they will all keep within thirteen
Ieet' whereas the Great Northern and City
tunnels have a diameter Of sixteen feet IFS
projectors adopted this size partly in order TO
accommodate wider rolling stock than is used
on the other lines. but also with the hone +bot
they would secure better ventilation Whether
or not there will be a material gain in tho
purity or the atmosphere, though is by no
means certain. With bigger cars than the other
roads employ, the available space will Doubt
less be filled completely as in the smaller
tubes" Each track, it will be remembered
runs through a separate passage and the train
fills the bore loosely like a piston in q cylinder
1t would not be surprising il the provision now
being made by the Central London to promote
| the circulation of air with powerful fans would
give its patrons advantages superior to those
enjoyed in other tunnels In the British me-
troDols.
Another unique feature Of the Great North
ern and City's tunnels is the character Of their
| lining. The lower half is brickwork and the
upper half iron, whereas the other tubes" are
! lined entirely with metal. By this innovation
IT was believed, the noise and vibration OBJ
served along the other tunnel routes might be
avoided. Possibly such may prove to be the
case, though the writer of the article in "Ihe
Engineering Magazine" 0dduces no testimony
IN support Of that view. On the other hand
he admits that the evils referred to have al
road hpon ,frfr d M
trains on the Central London. Waterloo and
City and City and South London lines were
originally hauled by heavy electric locomotives
These have now been abandoned on the first
two systems. and the multiple unit method
mat which is in use on the elevated roads Of
New York City-has been substituted The
change has perceptibly lessened both the sound
and the tremors which attended the operation
or the older roads. 1t remains TO be seen
therefore, whether the interesting experiment
of composite" tunnel lining will give any
better results
1nasmuch as the subway In New-Yori City
is at all places wide enough to include from
| two TO four tracks, no question regarding ven
tilatlon ought TO arise here. 1t is reasonable to
! believe that the OF the multiple unit" DIan
| Of operating trains will keep the noise down TO
a low minimum. The steps taken to reduce tho
fire risks, too, may well be contemplated with
genuine satisfaction. Nevertheless, there is one
| point OF difference between the New-York sinh
way and the London tubes on which TOO
great stress cannot be laid. The latter yyera
not constructed by the "cut and csver'' systan
! but by true tunnelling. They were ut such a
low level that it was impossible to disturb tba
surface of streets except where stations were
TO be created The greater part of the under
ground road originally planned for New-York
| IS now completed, and it is too late TO protest