Improved System of Electric Train Signalling for Preventing Railway Collisions.
Year: 1891

page_text: Date of Application, 23th Sept., 1891-Accepted, 9th Apr., 1892
COMPLETE SPECIFICATION.
Improved System of Electric Train Signalling for Preventing
Railway Collisions.
A communication from abroad by EUGENIO ESPIAU and PEDRO FERRER,
both of 5, Place de la Constitution, Barcelona, in the Kingdom of Spain,
Inventors.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.1.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street Liverpool and 6 Bank Street,
Manchester, both in the County of Lancaster, and 323 High Holborn in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
Numerous systems of signalling have been hitherto adopted for preventing
accidents on railways, which take place with sufficient frequency in most countries.
In spite of all efforts very few of the systems actually in use possess in their
working the conditions of certainty, and some of them even have been, by reason
of want of care or by the negligence of the railway employees, the cause of
unfortunate accidents in the place of preventing them.
The present invention has for its object an improvement in such systems. This
invention consists in providing a means by which the driver of a train shall be in
constant communication with the next station or even with the train which is
travelling on the same set of rails in an opposite or in the same direction as the
first one, thus allowing of its course being arrested in time, thanks to suitable
signals, to prevent a collision which would otherwise take place.
This invention will now be explained, reference being made to the accompanying
drawings.
Referring to Figure 1.-M and N are two stations connected by the track A B C.
In all the locomotives of the railway company an electrical dynamo is fixed,
capable of producing an electric current sufficient to overcome the resistance which
a rail of the same track offers in the maximum distances existing between the
stations of the above named company. This electric dynamo is placed on the
platform of each locomotive and at such a point D D' as not to hinder the work of
the drivers. This dynamo is actuated by the locomotive itself by means of a system
of gearing. The current is then directed, by means of a combined contact device,
which may consist of small brushes similar to those of the dynamos, on to one of
the rails of the track which serves as a conductor for it. In the drawing, the
rail E E takes the current from the dynamo D fixed on the locomotive L and
transmits it along all its length up to E, close to the next station where there is an
interrupter in the above named rail and a contact device o which forces the current
to travel by the conductor o' o" and transmits it to an electrical apparatus G for
receiving the signals which may consist of a little bell or any other suitable
apparatus. The electric current is produced by means of a dynamo-electric
machine carried by each locomotive and actuated by the motive force of such.
One of the poles of the dynamo is in communication with one of the road rails
by means of a brush E, Figure 4, which keeps constantly rubbing on it. The
other pole is fixed to the receiver H, Figure 1, placed on the locomotive L and the
other extremity of its conductor communicates with a button or manipulator, by
means of which the current is established or interrupted.
The other conductor of this manipulator communicates, by means of another
brush, with the other rail, by which the returning current is conducted.
It will generally be found convenient that the rails be insulated from one another
and the earth.

page_text: The rail which conducts the transmission current communicates with the bell of
the station N by means of the conductor o' o", and the returning current is carried
by the other rail fixed to the bell or sounder G by means of another conductor
similar to oo and on which and in proximity to the hell G a button is placed,
by means of which the current for working the signals beforehand is established
or interrupted, the whole not unlike the system of telephone bells.
In the same way, the apparatus is fixed in the station M, that is to say, the
mechanism is constantly in communication with the two stations between which
the train is travelling.
The part in which the rails have been referred to can be applied without any
essential difference to the system of conductors described and represented in
Figures 2, 3 and 4, in which there is the necessity of having two conductors and
two sets of brushes, one for the transmission of the current that is sent out, the
other for the reception of the incoming current.
In case two trains are in progress and on the same line but in an opposite direc-
tion, in having the apparatus fixed as explained, the dynamos of the two locomotives
will be connected in series by means of the rails or of the conductors described,
and the bells of the one locomotive and of the other rest in the same circuit; the
engineer, by means of buttons or manipulators, is kept informed as to the signals
in advance and knows perfectly his position.
In the locomotive and on the same circuit, a current interrupter is placed to allow
of suitable signals being made, and another in the station having the same method
of action. The signals both from the interrupter in the locomotive and in the
station are transmitted to another receiver H, which is carried by the locomotive.
In this manner, the driver or conductor of the locomotive I. is in constant
communication with the officials at the next station N, and the latter may easily
give the former warning and perfect certainty of the presence of a train on the
same track. There must be two receiving devices in the station, one for trains
arriving, which communicates by one rail, and the other for departing trains, which
communicates also by the other rail of the same track.
In case the station master shall allow a train to pass whilst having another on
the same track, the circuit will remain closed by the dynamos of the two corre-
sponding locomotives, which will compel the drivers to be in communication and
thus avoid immediate danger by having sufficient time for slackening the speed of
or stopping their respective trains. The portion of the track corresponding to the
platform of a railway station remains entirely insulated from the current by means
of interrupters or even by interruption of continuity which exists in the rails; this
can be seen on the accompanying drawings.
Although the rails may be insulated by substances which are bad conductors of
the electric fluid, the system can be applied without recourse being had to
insulators, seeing that the dynamos employed will produce sufficient electric energy
to re-establish the current on the rails, capable of causing the indicating apparatus
to operate in spite of the loss, inasmuch as the rail is in any case a better conductor
than the other constituents of the track.
If it be desired to increase the certainty of the transmission of the current, it
may be conducted along conductors placed parallel to the track, instead of utilizing
the rails themselves for this purpose.
In order to obtain this result, two systems, on the same principle, may be
employed, which however vary in their details; the first is represented by
Figures 2 and 3 of the accompanying drawings and it consists in arranging the
conductor in the shape of a small rail A A along the whole course of the track on
which it is desired to establish electrical communications. The current produced by
the electric dynamo placed at D, Figure 1, is transmitted to the conductor A, by
means of the rollers D (Figures 2 and 3) which rests thereon whilst revolving and
which in its turn receives the current by the shank E and the brush F, which rubs
constantly on the roller.
In order to ensure a good contact between the roller D and the conductor A, a

page_text: spring G¹ is employed, which has a tendency to cause the holder F to descend
and consequently to press the roller against the above named conductor. This
conductor A. A is maintained along the track by means of supports B, which are
fixed on the sleepers and insulated in any suitable manner.
The other system which may be employed for the transmission of current is.
more economical and is represented in Figure 4.
It consists in arranging a
cylindrical and flexible conductor or ordinary wire A A along the track, which is
held by insulators B B supported by supports CC fixed to the sleepers D D..
The current is transmitted to the conductor AA by means of a metallic brush E
which constantly rubs on the latter. This brush is held by a rod which has a
tendency to press it against the conductor, owing to a spring similar to that
employed in the arrangement previously described and which is not shown on the
drawing, being merely a repetition of the same mechanism. Also in both of these
systems when it is a question of traversing a level crossing, the conductors may be
placed under the ground to the extent of such crossing, so that the communications
will be interrupted for the moment, which does not cause any obstacle in the good
working of this system of signals.
The conductors may extend up to the track, either in the centre or front of the
railway stations. If it be preferred, a portion of the track corresponding to each
station may be left insulated.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is :-
1. A system of electric train signalling for preventing collisions on railways,
which consists in placing in each locomotive an electric dynamo working by the
motive force of the locomotive itself, and transmitting, by means of the rails, the
electric current produced, and by forming a circuit in which there are two trans-
mitting apparatus and two receivers, which allow the driver of a train to be placed
in communication with the nearest station master or even with the driver of another
train, travelling on the same track and provided with similar apparatus, substan-
tially as described.
2. In a system of electric signalling to prevent collisions, the employment of
conductors suitably insulated and to which the said current is communicated by
means of rollers and metallic brushes which in their turn receive the current from
an electric dynamo placed on the locomotive, substantially as described.
3. The herein described arrangement of parts, forming the improved system of
electric train signalling, for preventing collisions on railways, substantially as set
forth.
Dated this 96th dex of September 1891.
WM. P. THOMPSON & Co.,
Agents for the Applicant.