Improvements in and in connection with Railway Signals.
Year: 1893

page_text: ate of Application, 4th Nov., 1893-Accepted, 8th 8 pt., 1894
COMPLETE SPECIFICATION.
Improvements in and in connection with Railway Signals.
I, KARL RÖDLER of Hauptstrasse 9. II, Dresden, in the Empire of Germany,
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 :-
It is a well known fact that the means at present employed for protecting trains
have considerable uncertainty of action, this being sufficiently shown by the
railway accidents which still happen frequently. All the inventions in this field
have hitherto proved unsuccessful for the reason that it was attempted to effect
everything by the train itself, without the concurrence of the working staff; and
this of course gave rise to the employment of devices too complicated for ordinary
practical work. Now the present invention relates to an electrical means of
protecting trains which has not only the advantage of great simplicity and
certainty in working, but which also insures the accurate checking of the staff.
In the accompanying drawings
Figures 1 and 1ª represent a track between two stations, the distance being
divided into two principal parts, each of them being sub-divided into three parts,
it being supposed that one train is in the station and that the starting signal is
given.
Figures 2 and 24 represent the same as does Fig. 1, only here the train has
already passed the first signal (protection of the station).
It should be explained that the drawings are made in accordance with the
German system of railway signalling under which the elevation of the semaphore
arm indicates "line clear." (In England, as is known, practice is the reverse
"line clear" being indicated by a depression of the semaphore arm).
Figures 3, and 34 represent the same train protection, only the train is at
signal 5.
Figures 4 to 8 represent details.
The present arrangement requires only one current for all trains going in one
direction, hereby an earth return is supposed to be in existence.
The drawings represent a line with one track only. In a track with a double
line of rails, the arrangement is of course much simpler because in the latter case a
collision between trains in opposite directions is practically impossible.
A tunnel is supposed to be between 2 and 3 and at 4 a deep gap near a curved
track is assumed and, therefore, the intermediate signals will be necessary.
In the drawings, small letters of reference are used to indicate all those parts
belonging to the direction of travel from the station A to B, whilst the parts
belonging to the opposite direction of travel are indicated by capital letters.
For the sake of clearness, the conductors are represented as follows:
1. By a thick unbroken line for the trains travelling from station A to
station B, as far as signal 4; and by two dotted double lines from signal 4 to
station B.
2. For the trains travelling from station B to station A up to signal 2 by a thick
dotted line, and from block 2 to station A by an unbroken double line.
When a train is to be started from station A, the official at this station makes
contact by means of the lever f, upon which the signal "line clear" is given

page_text: ⋅
"
i.e. whereupon the semaphores of signals 1, 2, 3, that is to say s¹, 2, 3 show "line
clear which results from the attraction of the armatures n¹ to n³ by thei
respective magnets m¹ to m³.
In this case, the path of the current is as follows:-
From the battery c, through lever f, to the bell e of the station A, then to bell e
of the first signal and from here through the conductor 5 to the contact 6 of the
switch disc 50, thence to the contact 7 conductors 8, 9 contacts 10, 11 conductor 12
to magnet m' and thence through conductor 13 which transmits the current to
signals 2 and 3 in the same way as the conductor 5 transmitted it to signal 1 and
thence through the switching off lever d to the earth. For the explanation of the
path of this current, I give an accurate description of the corresponding
switch disc.
In a frame (Figure 4) two shafts u and u¹ are arranged in such a manner that
each may be turned independently of the other; the shaft u carries almost on a
level with the rails an angle lever t, t¹ and beneath it the switch disc proper 50
which has on its upper side three annular shaped contact pieces 10, 14 and 18
insulated from each other and on its under side small annular shaped contact
pieces 7 and 24.
On the lower end of the shaft u is a semi-circular disc w provided with a slot vl.
This slot receives a pin v of the chain disc 60 which is carried by the shaft u and
is connected by a chain 61 with disc 62, the latter being turnable around the
pivot . The disc 62 may be actuated by a lever g, operated by hand. This
lever is provided with two notches in order that it may be placed against the
lugs and g. The switch disc 50 is represented in its three different positions in
the Figures 5, 6 and 7 and here above the disc contacts are represented in unbroken
lines, and those placed under the disc by dotted ones.
As soon as the train arrives at signal 1 it puts (by means of a disc 2, Fig. 8,
operated by the driver of the locomotive) the switch disc 50 out of the position
shown in Figure 5 into that shown in Figure 6.
The arrangement of the disc z is clearly to be seen in Fig. 8; through the sleeve
cup passes the threaded spindle y which may be lowered and lifted by turning the
hand wheel a; and, hereby, the disc z is brought either into working position or
to that of rest. Corresponding to the two switch discs, one for each direction of
the train, the locomotive is provided with two discs which are operated according
to the direction of the train.
If the train has left signal 1 and if the switch disc, as mentioned above, takes
the position represented in Fig. 6, the current does not pass as before, through
the signal magnet m¹, but directly to the next signal.
This will be better understood by reference to Fig. 6. The current having
passed the conductors, reaches the contact piece b and the under annular shaped
contact pieces 7; whereupon it is conducted, as before, to the wire 8. The
conductor 9 cannot let the current pass because the circuit is interrupted between
the contacts 10 and 11; but the current may go through the wire 17 to the upper
annular shaped contact piece 18, which is now in contact with 19 and, therefore,
the circuit may take its further course through conductor 20 to the wire 16; and,
hereupon, it is conducted to the next signal. From this, it will be seen that, if the
train leaves the first signal, the arm of the semaphore is brought into the position
of danger; therefore, the train is protected; but the bells e and el go on quietly.
ringing and announce in this way that the train is still between blocks 1 and 4.
Supposing now that the train goes on it will move the arms of the semaphores at
signal 2 and 3 into the "danger" position and the corresponding bells will go on
ringing. About 300 metres behind the 4th signal, i.e. as far from it as is the
average length of a train, a switching off lever d is arranged and is moved by
the disc to interrupt the current when the train has passed the first block
division.
If the current is interrupted at A, all bells cease ringing. The official at A is
thus made aware that he must interrupt the current by means of his lever f: at

page_text: the same time the operators at the semaphores are reminded that they have to pul
their switching discs into normal position. For this purpose, the operators take
their levers g in hand, push them to the lug g² and then bring them back to g².
Thereby, the switch disc 50 is first brought into working position; and, in
bringing back the lever, the pin v travels through the slot v¹; thus, if this disc is
worked from the train the slot v' slides round the pin ; and, therefore, the lever g
remains unmoved. In almost exactly the same way the disc 50 destined for the
opposite direction of the train is turned by help of the lever G; ouly, in this case,
the turning (of the disc) takes place in the opposite direction and the chain 63
provided for this purpose must pass over suitable pullies.
If, by mistake or negligence, a second train leaves A. before the first one has
passed signal 3, the second train will move the alarm signal 22 by means of the
lever t; and the train is at once stopped because the disc 50 takes the position
shown in Figure 7 and the current coming from the conductor 5 passes through
the wire 21, the alarm signal 22 the conductor 23 contact pieces 24 and 25 and
thence to the conductor 16. An explosive capsule is best used for signalling
If this
danger as it shows fire in exploding when the current passes through it.
has taken place before the leaving of the block 3 by the first train, the officials on
such train will be informed together with the operator in question of the leaving of
the second train; because, by the current interruption, the semaphore arms indicate
danger and the bells cease ringing.
Of course, by means of slight alterations, the alarm signal may be shown without
interrupting the current, in such a manner that the operator at the next station and
the officials on the first started train will not be informed of the wrong starting of
the second train.
If a train starts from station B, after the departure of another train from A in
the direction of B, the signals s¹ to s³ as also sto s are brought into the position
"line clear" and at signal 3 the semaphore arms for both directions will rise.
The armatures n³ and N³ receive levers p and P swinging round o and O; and,
thereby, as soon as they are attracted by the magnets m³ and M³, contact between q
and and between Q and R is effected."
The current coming from the battery will now pass through the magnet m³ but
not, as usual, reach the conductor B but go across q, r, the alarm signal 30 the
contacts Q, R, to the conductor 16 and further on in the manner known to
earth.
Therefore, the alarm signal 30 will act and discover the inattention of the official
concerned because the driver of the locomotive, after having reached the block 3
will see that no trains are signalled "line clear."
As only one switch lever (F) is provided at each station the signals to enter and
to depart can never be given at once from the same station.
Having now shown that two trains cannot come into collision either when running
in the same or in opposite directions on a single line of rail, I will explain the
means by which the officials are controlled.
As mentioned before, the station master and the semaphore men have to move
their respective levers, if the bells cease to ring, which takes place if the circuit is
interrupted at d (D). After this the man at the fourth signal has the duty of
closing the circuit at d. The station master at A has to interrupt the current
at fand the semaphore men are at the same time signalled to bring their respective
switch discs into the original position by means of the lever g (G). This original
position may be also given after the starting signal has been given by f. If one of
the above mentioned officials has not done his duty, this will be quickly seen at
different places as may be understood from the following explanations:-
:-
1f, for instance, the official at the fourth signal forgets to close the circuit d and
at the same time a train is to be started from A, neither of the bells is able to ring,
nor can the semaphore arms be brought into the position "line clear"; facts which
must be remarked at station A and at the signals 1 to 3. If the station master
at A forgets to interrupt the circuit by his lever f, the semaphore arms are uselessly

page_text: -
brought into the position "line clear” and, therefore, the omission will be apparent
at once and at several places.
If one of the semaphore men should forget to return his switch disc into the
initial position, the alarm will be operated at the corresponding signal if a train
passes, thereby showing neglect on the part of the corresponding official to return
the switch disc into the initial position, and thus the responsibility can be brought
home to the party at fault.
CLAIMS.
1. An electrical system for the protection of trains by means of which on
dispatching a train from a station, a circuit is closed by an official at that station
and the bells of one block division begin to ring, the distance signals and block
signals of this division indicating whether the line is free and if one of these siguals
has been passed, the circuit is automatically re-established by the train and the
respective semaphore.arm indicates danger whilst its signal bell still remains in
operation till the train has left its block division, whereupon the current is
automatically switched off and the signal bell ceases to ring.
2. A method of carrying out the system of train protection, claimed under
Claim 1, whereby when a train leaves a certain station the official in such station
makes contact so that the signals of a block division show "line clear" and all bells
belonging thereto are set ringing; whereupon, by a disc outside the train, (upon
the passing of the signal by the latter), a switch disc 50 is put into such a position
that the current leaves the magnet contained in the apparatus of the signal in
question and the semaphore arm takes the position "danger," whilst the signal bell
continues to ring until the train has left the block division and the current is
interrupted by a switching off lever d, whereupon all the bells cease ringing, thus
showing the official at the starting station that he must operate the switching off
device; and also notifying the signal officials that they must return their switch
discs into the original position.
3. Another mode of carrying out the method of train protection claimed under
Claim 1, according to which if a train starts from a certain station, a contact is
made by the official there whereby the signal bells of a block division are set in
motion and hereby the operators reminded to bring the switch discs into the
original positions if the line is free and, therefore, the signals of these block
divisions indicate that the line is free for the train whereby a disc outside the train,
in passing a signal puts the switch disc 50 into such a position that the current
leaves the magnet of the apparatus in the signal in question and thus the semaphore
arm indicates "danger" whilst the signal bell goes on ringing until the train has
left the block division in question and interrupts the current by a switching off
lever d, whereupon all bells cease ringing, which fact notifies the official at the
starting station that he has to operate his switch lever.
4. A further mode of carrying out the system of train protection, specified under
Claim 1, in which a switch disc 50 is arranged in such a manner that, if acted upon
from a passing train, it assumes such a position that, should an undue train come up
behind, the disc will be brought into such a position as will effect the closing of a
contact whereby an alarm signal is worked and the train in question is stopped at
the same time all signal officials of one block division are informed that there is
danger" or that there is something wrong within their block division, either
because the bells in the block cease ringing before the switch lever d is put into
operation or by the continuous ringing of all block signal bells of a block division
by which arrangement of the switch disc all the officials may be actually controlled,
because if any official should neglect his duty, that is to say, should fail to interrupt
the current or to move the switch lever, this would be indicated several times either
by the giving of wrong signals or by the appearance of warning signals, without
any collision being possible.
5. The arrangement and combination of switch discs acting substantially as and
for the purpose specified.

page_text: 6. The employment of the alarm 30 substantially as and for the purpose-
set forth.
7. The general arrangement and combination of devices for protecting trains,
substantially as set forth.
Dated this 4th day of November 1893.
KARL RÖDLER,
Per J. G. L.