# Basic elements of signaling system

3.1. Rail circuits (Train detection):
Used in the determination of train locations
equipment may be of different types.
Algebraic Ray Circuits:
Electrically separated from each other with isolated algebras
checking the voltage applied to rail zones
and the presence of the train. Rail line with algebra isolated
after these regions
a supply voltage is supplied by
voltage control from the other side of the rail zone
It is. If voltage is applied from isolated zone
If you are receiving a return voltage in the rail area
There is no train. Two rails when the train enters a rail zone
short circuit. In this case applied to the rail
in the region where the voltage will not be reversed
The presence is understandable. Here reverse train detection system
works with logic. So if there is voltage, no train, voltage
otherwise there is a train. The reason for this is the error
safe operation. Any
One reason (cable break, short circuit, equipment
failure etc cannot be recovered due to applied voltage
the train in the area is considered to be the
accidents to be the safest
Prevented. All older systems
Circuit is. Istanbul LRT Line, Izmir Metro and
TCDD isolated algebra in suburban and suburban lines
Rail circuits are used.
Coded Rail Circuits:
Coded ray zones with rails isolated algebra
no need to separate. Rails instead
capacitive separators are used. The Ray
sound frequency
taken from the other end of the track by means of a receiver
and measured (Figure-1). If there is a deviation in the frequency
According to the fail-safe logic is considered to be a train and
The zone is locked. Built in recent years
block systems with sound frequency
It is used. Especially the short distances of the vehicle
low-time train requiring detection
It is advantageous to use in operating systems.
In addition, the rail is uninterrupted in the comfort of the journey
increases and maintenance costs are reduced. Recently
Ankaray rail systems and Taksim -
4 Levent Istanbul Metro track coded circuit
It uses.

Figure-1: Example of a simple sound frequency track circuit
Axle Counter Rail Circuits:
By counting the remaining axles entering the rail zone
it is the rail circuit that understands whether or not it is in the region. if
the number of axles entering the area is not equal to
With the fail-safe logic in the area is considered to have train.
Rail circuit especially in intercity rail systems
prefers Axle Counter (Figure-2) in new systems
It is. Axle counter isolated system in the counter
It is easy to maintain and does not use the rail
the journey is more comfortable. our Country
On the Bursaray Line
used. In the world, especially intercity

Figure-2: Axle counter examples [11]
Moving Block Rail Circuits:
In the moving block signal system the rail circuits are virtual
and the length of the train speed, stop distance, brake
power according to the curves and slope parameters of the region
change. The program in the control center
automatically adjusts the distance in front of
lowers or raises speed. In this way the rail circuit
The distance used will be short or unnecessary
increases the capacity of the line as it will not be held long.
Usually at line capacities at 90 sec and below
It is more economical to use. Ankara in Turkey
block signaling system
used.

Figure-3: Moving block signal diagram
3.2. Signals:
At the beginning of each track or path entry
trains
traffic lights. Red stop, green late
It is beside the point. Usually if the train passes the red light
stop automatically. Signal systems
technology (bikin, inductive loop, different rectifier)
lamps, GSM-R etc.) of each signal zone
at the start of that rail circuit section speed limits
information is provided to the train and safe navigation is provided. Moving
blocks in the signaling system can change blocks
There are no signals along the line only for the station or
scissors can be placed according to need.
3.3. Scissors:
The changes in the direction of the trains are with the help of scissors.
Scissors are also fail-safe in the signaling system
according to the logic of the vehicle in the region or passed
does not take command in the case and related to the location of the scissors
also in case of a suspect
The controller is not allowed.

Figure-4: Simple Scissor signaling application
3.4. On-board equipment:
From the signaling system on trains
the person who moves the train according to the field and
electronic unit that directs movement. train
most important
It is a component. On-board equipment
speed limit or other safety
warns the mechanic when the rules are not followed
and a lack of safety on the train (coupling)
breakage, opening of the doors, a fault in the brake system
vs) or a fault according to the signal system (on line
detection of an obstacle, defined maximum speed
etc, they stop the train. Automatic
in systems where there will be no excitation for the mechanic
security measurement methods have been improved and
safety train in case of emergency
stopping. signaling
Most of the accidents on systems are on-board
manual driving
occurs.
3.5. Interlocking:
All line length equipment in the control center
information is collected and according to this information is a rail of a rail
It is given. Any train to a scissor or rail area
when he left the rail zone
zone is locked and no operations in the area
is not allowed. Allow trains this way
block
ATC (Automatic Train Control) / ATP
(Automatic Train Protection)
clash / collision with trains
Blocked.
The central locking system was first used for relays
was done with. Relay of the region that is busy
and other commands. New
Systems are now fail-safe (Safety Integrity Level
3-4) software interlocking systems
It is used. Central locking systems at least 2
consists of industrial computer and made of
the operations are done separately on both computers and
The results are compared. If the results are different
The command is not applied. The functions of locking:
1. The whole route except the train
is locked by.
2. Route at every point where the train will change direction
The road is arranged with locking.
motorized scissors are correctly positioned and
mechanically locked.
3. Signal is arranged so that the train will watch
The presence of the train in the region is monitored.
4. With the passage of the train from the locked area
allow the passage of other trains
is automatically released.
The signals on the route on which the train moves
train
maintains the status.

Figure-5: Control Center
4. SIGNALIZATION SYSTEMS
Increasing capacity today and driving safely
specific to tramway systems
regional signaling systems are used.
On mixed roads in tramway systems
Applied in areas seeing driving, scissors and tunnel
In the regions, interlocking is provided with safety.
The logic of signaling in the tunnel area; the tunnel
light from darkness to darkness
stopping
trains cannot be noticed on 15 km
signaling system in the tunnel areas
It is established.
Today, many systems are basically
light metro and subway signaling
systems are installed.
1-Fixed block manual driving
2-Fixed block automatic driving
3-Moving block automatic driving
4.1. Fixed block manual driving signaling system:
Signal system signaling in this signaling system
directs the mechanic through the lamps.
Usually less than 10 minutes
timesheet application
the necessity was born. 10 on a system
if there is an expedition range under (Headway Time - HT)
trenler
between
the distance
protection
is required.
Constant
blocky
manuel
drive
not possible
it is not possible. In such systems
maximum
the experience of the mechanics is trusted. (E.
Istanbul and Izmir Light Metro lines)
10 the capacity of the line if a ride according to the experience
train ranges less than the headwayden
and Machine Engineer
Systems (DIS) and Vehicle Tracking Systems
(eg Ankara and Bursa)
Light Metro lines).
4.2. Fixed block automatic driving signaling
system:
In these systems with automatic train operation system
trains control center by computer
it is automatically driven. Time
Timetable
is saved in. How fast is the train
sometimes at the beginning of blocks or by continuous train
communication. Central
interlocking detects the position of trains and stops
the point and how safe
informs the train. According to the information on the train
calculates the required braking force and applies
Applies a brake force according to.
If train frequency is low
during the initial design of the signaling system (eg HT
= 90 sec. or 120 sec.) length of rail circuits short
It should be maintained. Difficult to implement at low train intervals
2 with train
is a convenient solution. Manual driving
10-15 more than signaling system
the cost of driving synchronization,
energy and personnel savings
is a solution. Taksim - 4 Levent from Istanbul
Metro uses this system.
4.3. Moving block automatic driving
The latest development of signaling systems
point. The first researches started in 1960 and
First Fully Automatic - Driverless after trials
Rail System 1983 in Lille in France, Siemens
was built and put into service.
To date, all major rail system manufacturers
continue to improve by working on these systems
they have. Nowadays, the communication system
CBTC continues its development with CBTC.
The control center is furnished along the line with each train
communicates via leaky cable or wireless network.
In systems communicating via the wireless network
High security of signaling
communication system is redundant, so double
channel communication is used and field information
compared on train. Which line of trains
at which point (dopler radar, GPS, vehicle)
With the help of km counter vs this location is determined) train
to the control center. Every train,
how close to the train in front of the speed of the train,
is calculated and sent to the train and the speed of the train accordingly
readjust. The region where each train is located
it is locked separately and the speed of each train is calculated separately.
Typically 90 sec. attractive for less time intervals
is a signal system. 90 expeditions
sometimes expensive for a signal system at intervals
passenger density
Suitable for lines. Especially in recent years IEEE
Communication to the standard as an open code by
Train Based Train Control
Control-CBTC systems do not depend on a single company
It is also advantageous. I mean a company
is the other signal firm
so that you can extend and extend