The Sun.
London, England, 1858-03-03 00:00:00

AUTOMATIO RAILWAY S'IgNALS.

Several scientific (Yen, leuaan iissemVed on Satur-
day at the works of Messrs. Collings, the engineers,
in Lambeth, to wituess a trial of a new system of
railway signals: which have recently been patent sd
under the tide of " Martin's Patent Automatic
Railway Signal Apparatus," and which is about to
be introduced experimentally on some of the sta.-
tious of the Great Northern Railway. The in•
vention combines three great rev:sites for a pi r-
feet system of railway signalling--simplicity, self
action, and, as much as po;sible, certainty. Its
purpose is to perform all the duties of the ordinary
semaphore signals without the aid of signal-men,
by means of the trains themselves. The apparatus
consists of a wrought-iron lever, xed to the insides
of the rail at the signal station, which communi-
cates by means of an axle to cranks passing under
the rails with the semaphore. On the train passing
over this lever, it presses it down, and its action
upon the iron-work beneath, and the crank raises
the semaphore arm, which it retains in its place
until the train has p asses the next station, when
the same operation taking placa there, lowers by
means of hydraulic pressure the signal arm at the
previous station, and shows that the line is clear.
Probably the scientific public will better under.
stand the apparatus from the description given by
the patentees themselves, which we therefore sub-
join :—" Inprinciple it is the same as the ordinary
pump, but in action the reverse ; for general ilhis-
tration we will instance the reporting of a train
each mile of its progress ; one mile from the
terminus is fixed an ordinary signal post, and
so on at each mile, say from London to Li-
verpool ; the train on leaving the station raises
a signal by means of a lever fixed at the side of the
rail, which is operated upon by the rim of the wheel
passing over it, at the same time raising a piston in
a cylinder, filling it the length of the stroke with
flail (not affected by heat or cold), the valve con-
nected with it at once closing prevents the pistan
returning until the train arrives at the next signal
post, when the same operation is performed, but,
the fluid this time raised is drawn by means of a
tuba or pipe connecting it with the previous cylinder
underneath its piston, thereby allowing it to fall
and lower the signal, but the time at which shall
fall is controlled by the weight fixed on the lever,
and the proportion between the size of the cylinder
and the pipe or tube. In the apparatus now een-
struoted for the Peterborough station of the Great
Northern Railway, the cylinder is three inches
diameter ; the tube three-eighths of an inch. These
sizes, with a weight of 1001bs., will lower the signal
in 100 seconds; but as it is necessary in this instance
that the signal should remain five minutes after the
train passes the next signal post, a proportionably
smaller weight is employed. In a similar way the
signal arm at the second station is lowered when the
train arrives at the third station, and so on thus
throughout the whole length of the line when th's
apparatus is applied. Whenever a train passes
a signal station a signal will be raised at that
station, and this signal will not be lowered until
tho train arrives at the next signal station ; hence
it will be seen that the engine-man and
guard of the train, in 'coming up towards a
signal station, will at once ascertain whether the
preceding train has passed the next distant Sign:6l
,tation ; for night trains or foggy whether it will
act by operating on the whistle, or, if found
necessary, cutting off the steam; thus allowing
trains, under all circumstances, to pursue their.ordi-
nary speed ; it is also particularly applicable to all
station signals, at junctions of lines, by a reverse
action in signalling an approaching train, and to
every position where a signal is required. From.
the Parliamentary returns the chief cause of loss of
I;fe and limb arises from collisions ; these, in the
majority of instances, arise from insufficient signal-
: the approach or passing of a train can be re-
ported by itself with a greater certainty and exac-
titude than by human vigilance, liable to err from
many causes. In a pecuniary point of view, to
railway proprietors, it effects by its first cost an
immense annual saving in the salaries of signal-men
alone ; in its construction care has been taken to
avoid complication or lightness in any of its parts,
and it may be said to be as durable as the rails, and
as little or less likely to derangement." As far as
experiments conducted within the limited area of
an engineer's yard in London affords an oppor-
tunity o! judging, this system appears to approach
p.s near perfection as possible, and that was the
ipinion expressed by several gentlemen of the engi-
neering profession acquainted with the practical
working of railways who were present. The paten-
tees assert that distance is no object, and that the
apparatus will work with equal certainty whether
the signal stations are 100 yards or four miles
apart ; the only difference being that in one case a
larger amount of hydraulic pressure has to be em-
ployed than in the other, and this is effected merely
by increasing the size of the tubular aqueducts from
half an inch to three-quarters of an inch in bore,
and so adding to the volume of the fluid. It is but
right to add that the experiments of Saturday were
confined to the day signals, the absence of the prin-
cipal agent in the night signals, the locomotive
itself, rendering it impossible to test how far the
statements of the patentees as to the efficacy of
their apparatus forsignalling in the dark are borLe
out by actual results.