Electrical Indicating Railroad Signalling.
Year: 1897

page_text: Electrical Indicating Railroad Signalling.
GEORGE GRIFFITH 5 Carlton Terrace Sydenham Park Sydenham in the Parish of
Lewisham Electrical Engineer do hereby declare the nature of this invention to be
as follows:
By placing Electrical conductors at desired spaces either above between or at the
side of the railroad and an appliance on the Locomotive which when passing makes
electrical contact. On the Locomotive and in the signal box are placed indicators
which give corresponding signals, an arrangement placed at the side or above the
railroad which gives an alarm to the driver and rings automatically an electric bell
in the signal box to which is attached an indicator to shew which signal the
Locomotive is approaching this warning is repeated after the locomotive has passed
the signal.
Electrical Indicating Railroad Signalling.
GEORGE GRIFFITH Electrical Engineer 5 Carlton Terrace Sydenham Park
Sydenham Kent 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 :—
My invention relates to rail road signalling and has for its object to provide an
improved apparatus connected with the signal lever, whereby an indication on the
locomotive will be given of the state of the signal which the train is approaching.
According to my invention I provide at suitable distances from each signal, electrical
conductors either above, between or at the side of the rails, with which conductors an
insulated brush carried by the locomotive is adapted to make connection. Said brush
is connected through an indicator in the cab to the frame and thence through the
wheels and rails to the earth wire which is connected with one or either pole of a
battery to a reversing switch. The other terminal of the reversing switch is
connected, preferably through an indicator in the signal cabin, to one of the
conductors before a signal post and the reversing switch is in operative connection
with the lever working the corresponding signal.
A bell is preferably provided in the circuit in the cab of the locomotive in order to
give the driver warning that he is approaching a signal and attract his attention to
the indicator and a similar bell may be provided in the circuit at the signal cabin,

page_text: The indicator at the cabin is merely a repeater which informs the signal-man that
the correct indication has been given on the. locomotive.
In order that my invention may be clearly understood I will proceed to describe
the same with reference to the accompanying drawings in which,
Figure 1 is a diagram shewing the electrical connections.
Figure 2 is a diagrammatical view illustrating in detail the connections in the cab
of the locomotive when the train is approaching a signal, and,
Figure 3 a similar view when the locomotive is not approaching the signal.
A indicates the conductor at the side of the rails which is supported by an
upright A¹ and provided with a hood A² to protect it from the weather.
A3, is a brush supported by means of a spring from the locomotive, said brush is
insulated and adapted to make contact with the conductor A as the locomotive
travels on the rails.
B is the indicator in the cab, C the bell, D the metallic portions of the frame,
E the wheels, F the rails.
In Figure 1, G is a signal post the arm of which is worked in the usual manner by
a lever H in the cabin. Said lever is operatively connected through a link H¹ with
the arms I of the reversing switch. J is the battery, K the cabin indicator, and
L the cabin bell.
The electrical connections are as follows:-
The conductor A is connected by a wire a to the cabin indicator K which is
connected through the bell L to the middle terminal b of the reversing switch, the
other two terminals 61 of the reversing switch are connected through a wire C with
the rails F.
The insulated brush A³ is connected through an insulated wire d to the indicator B
which is connected through the bell C to the frame of the locomotive.
It will be understood that each signal has its own cabin indicator and reversing
switch, the latter being connected with the signal lever.
The signal indicator which may be of the same type in the cabin and on the cab,
is of any suitable type having a pointer which takes up three different positions, one
when no current is passing, another when a current is passing in one direction through
the circuit, and a third when the current passing in the other direction through the
circuit.
The indicator illustrated in the drawings consists of a coil of wire having a magnet
pivoted inside it to which magnet the pointer B¹ is attached, When no current is
flowing said pointer stands vertical but when a current is flowing it moves to the
right or to the left according to the direction of the current.
The reversing switch may be of any suitable type. As shewn in the drawings it
consists of two levers I, I connected together by an insulated link I¹ each said lever
being in electrical connection with one pole of the battery J. In one position of the
switch the positive pole of the battery is joined to the terminal b in the other position
of the switch the negative pole of the battery is joined to said terminal. . Other
descriptions of reversing switch may however be employed a useful form being one
in which the signal lever has electrical contacts secured to it and acts also a switch
lever.
The operation of my improved apparatus is very simple and it is as follows:-
When the locomotive is approaching a signal the insulated brush A³ carried thereby
makes contact with the conductor A appropriated to that signal. If the signal lever
has been drawn to move the signal arm to "line clear" the reversing switch will be
in such a position that the current passing through the circuit will cause the
indicator B on the locomotive and the indicator K in the cabin to shew "line
clear" if however the signal lever has not been pulled the reversing switch will be in
the other position and the indication "danger" will be given. When the locomotive
(as shewn in Figure 3 for example) is not approaching a signal the brush A³, will be
entirely insulated and no current will pass through the indicator on the locomotive
also the circuit of the battery at the cabin will be broken.
It will be observed that by the use of my improved system an indication will

page_text: be given to the driver of the locomotive of the state of the signal which he is
approaching, the train service will therefore be enabled to proceed in foggy and
thick weather as if it were clear. Another advantage of my improved system is
that it can be applied to existing signalling appliances without alteration of the
same by merely using additional apparatus.
.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, declare that what
I claim is:
1. For use in railroad signalling an apparatus comprising an indicator on the
locomotive connected between the frame of the engine and an insulated brush carried
thereby, said brush being adapted to make contact with conductors located near the
rails before each signal post, each said conductor and the rails being joined to a
battery through a reversing switch operated by means of the signal lever either with
or without a repeater indicator in the signal cabin, and with or without warning bells
in circuit on the locomotive and in the cabin substantially as described.
2. The method of communicating to a locomotive driver the state of the signal,
which consists in-sending a current through an indicator on the locomotive when
the same is approaching a signal, the direction of the current being varied by a
reversing switch connected with the signal lever substantially as described.
Llated LOIS OLD DAY OF UICLOner
Llated LOIS OLD AV OF UCLoner 1897
GEORGE GRIFFITH.
W. P. Thompson & Co.
322, High Holborn, London, W.C. Patent Agents for the Applicant.