This website is still in beta and it might have some errors
As of 2019, only 45% of the railways in Turkey are electrified and signalled. In signalled parts, a system called CTC is being used.
CTC consists of mainly 3 types of signals.
Tall signals are the most common type of these three. They can be mounted both on the right/left side of the track or on the top of it, using steel beams.
Small signals are only found in depots / sidings and are mounted on short steel pipes.
In case the main signal cannot be seen from a set distance, a repeater signal can be placed up to 400 m before the main signal.
These type of signals have the letter "T", telling that the signal is a "Tekrarlama Sinyali"
Before going deeper, let's see some basic examples:
In tall signals that do not flash, yellow over a yellow as in Figure 1 means that one block is free and the route is set for the diverging track.
In tall signals that do not flash, green as in Figure 2 means that at least 2 blocks are free.
Since small signals are found in sidings, the route is always set to the diverging track. Maximum speed over the switches is 30 km/h.
A flashing light as in Figure 4 means continue with "restricted speed" (sınırlı seyir) which is 25 km/h.
Next block is occupied. Orders a complete stop.
At least two blocks are free. Continue with the allowed maximum speed.
Only one block is free. Expect stop at the next signal.
In case where the next block is shorter than the braking distance, the previous signal is also yellow.
The route is set for the diverging track. At least two blocks are free.
Maximum speed over the switches is 30 km/h.
The route is set for the diverging track. At least two blocks are free.
Maximum speed over the switches is 30 km/h.
The route is set for the diverging track. Only one block is free. Expect stop at the next signal.
Maximum speed over the switches is 30 km/h.
The route is set for the diverging track. Only one block is free. Expect stop at the next signal.
Maximum speed over the switches is 30 km/h.
Next block might be occupied. Proceed with a maximum speed of 25 km/h and be ready to stop at any time.
Entering a signalled block. Proceed with a maximum speed of 25 km/h.
Continue at normal speed until the next signal.
Expect to stop at the next signal. The next signal is closer than 400 m.
Entering a signalled section. Obey the nearest small signal's order.
Entering a signalled section. Proceed with a maximum speed of 25 km/h.
For a train that is obeying the nearest small signal because of a "YS" sign.
Entering a signalled section. Proceed with a maximum speed of 25 km/h.
Next block is free.
For a train that is obeying the nearest small signal because of a "YS" sign.
Entering a non signalled section from a non signalled section through a signalled section.
Proceed with a maximum speed of 25 km/h.
For a train that is obeying the nearest small signal because of a "YS" sign.
Entering a signalled section. Proceed with a maximum speed of 25 km/h.
After the switches, at least 2 blocks are free.
In shunting operations controlled by the OCC, trains in non signalled areas cannot enter signalled areas in the same direction.
Proceed with a maximum speed of 25 km/h.
Tracks that are in the Marmaray line (Istanbul) are also equipped with the CBTC signalization system. This system allows for more than one trains to be in the same block, resulting in more frequent operations.
Signals in this line have one more light on top which is blue.
This aspect means that a CBTC-equipped train doesn't need to stop at the signal.
Signals that show any other aspect / are broken / don't have any visible lights order a complete stop.
In this case, the OCC should be called and orders from there should be followed.