Greek railway signalling

The first railway signalling in Greece was installed on the Athens–Piraeus Railway at the turn of the 20th century, when

Hellenic Railways (OSE) signalling

History

On lines currently operated by the

All current aspects of railways signalling are described in the document "Γενικός Κανονισμός Κυκλοφορίας - Μέρος Α - Κανονισμός Σημάτων και Παραρτήματα I, II, III, IV, V & VI". This is a collection of different regulations, the main part covering semaphore signals and lineside signs, with appendices covering new signalling systems. It was issued in electronic format by Hellenic Railways Organisation in 2009.^[1] The contents of this document include:

• Main body: Traditional signs and signals, reflecting signalling and operating practices as they were around 1970.
• Appendix I: Colour light signalling in Thessaloniki Railway Complex (New Passenger Station and Shunting Yard).
• Appendix II: Colour light signalling system initially installed in Thessaloniki-Platy and Athens-Inoi sections.
• Appendix III: Current colour light signalling system and procedures.
• Appendix IV: Special local signalling systems in Edessa Station and at Kalamata Engine Shed junction.
• Appendix V: Level crossing signalling system (Greek: ΑΣΙΔ).
• Appendix VI: Recently introduced signs for electrified lines.

Semaphore signalling

Semaphore signals followed the German pattern and consisted only of home signals (German: Einfahrsignal) with the corresponding distant signals, covering the entrance to stations and are described in Chapter II of the Signalling Regulation. There were no starting semaphore signals (German: Ausfahrsignale), as the trains were signalled out by the Station Master in person, holding up a staff with a green disk and blowing his whistle. This practice was followed when colour light signals were first installed in the sections Athens–Inoi Junction and Thessaloniki–Platy, even though the new system included starting signals, but it was abandoned later, with the introduction of the current signalling system.

Signal	OSE Code	Meaning	Next signal	Notes
	11b	Stop	-	Stop immediately and wait outside the station
	11d	Proceed		Entrance to station free, unless it is restricted by other signals.
	11e	Slow		Proceed into station, entering a diverging line at a junction or the secondary line of a passing loop.
	20a	Caution	11b	Reduce speed to stop at the main signal.
	20b	Caution	11e	Reduce speed to proceed with low speed after main signal.
	20c	Clear	11d	Main signal is clear

Radio communications

Around 1973, as a result of a serious train accident that took place between Doxaras and Orfana stations in Thessaly, the OSE installed

In recent years the OSE undertook modernisation of the section from Piraeus to Thessaloniki and Idomeni. This line uses block signalling with centralized control from a small number of signal boxes (Appendix III of Signalling Regulation). Signals are colour light signals with up to four lights and up to six possible aspects, which are described in the following table. Of course some signals have only three or two aspects when there is no need for all possible indications (for example if the signals are not followed by points). There are even a few single-light two-aspect signals, displaying either steady of flashing amber (ΦΠ-10 and ΦΠ-12). Currently the colour light signalling is functional on the following sections:

• Acharnai Railway Center
  to Inoi junction. (Appendix II, converted to Appendix III)
• Inoi junction to Tithorea (Appendix III)
• The single line mountain section from Tithorea to Domokos. It is the first section of the OSE network with full modern signalling and control from a central signal box located at Leianokladi (1982). (Appendix III)
• Domokos to Platy (signal box located at Larissa) (Appendix III)
• Platy to Thessaloniki, up to signal box TX1 (Appendix II, converted to Appendix III)
• Thessaloniki complex, controlled from five signal boxes (TX1 to TX5)
• Thessaloniki to Idomeni (Appendix III)
• Ano Liossia to Kiato (Appendix III)
• Acharnai Railway Center
  to Athens International Airport (Appendix III)

On the following sections the installation of signalling is at an advanced stage:

• Piraeus to
  Acharnai Railway Center
  , with the exception of Athens Central (Larissis) station.
• Inoi junction to Chalkis
• Acharnai Railway Center
  to Ano Liossia

Slightly different signalling systems were originally specified for the sections Athens–Inoi Junction and Platy–Thessaloniki; these are described in Appendix II of the Signalling Regulation.

Specialized local signalling systems exist at:

• Junction of Kalamata Engine Sheds (Appendix IV)
• Edessa station (Appendix IV)
• Thessaloniki Railway Complex (controlled from five signal boxes TX1-TX5)

The following table describes the modern (Appendix III) signalling system.

Signal	OSE Code	Meaning	Next signal	Notes
	ΦΠ 0	Stop	–	Signal must not be passed.
	ΦΠ 1	Proceed	ΦΠ 1 ΦΠ 10 ΦΠ 12	Proceed with maximum speed for section, unless it is restricted by other signals.
	ΦΠ 2	Slow	any except ΦΠ 0	Proceed with a maximum speed of 40 km/h from the signal to the exit of points area. Usually indicates that the train enters a diverging line at a junction or the secondary line of a passing loop.
	ΦΠ 10	Caution	ΦΠ 0	Reduce speed to stop at the next signal.
	ΦΠ 12	Caution	ΦΠ 2 ΦΠ 20	Reduce speed to proceed with low speed after next signal.
	ΦΠ 20	Slow. Stop at next signal	ΦΠ 0	Proceed with a maximum speed of 40 km/h from the signal to the exit of points area. Next colour light signal is red. Usually indicates that the train enters a passing loop while the starting signal at the other end of the loop displays a red aspect.

Signals are tagged with an identity which consists of a three- or four-letter code denoting the station and a number (for example "OIN 3"). Distant signals share the same number with the corresponding main signal with the addition of letter "A" in front of the number (for example "OIN A3").

Switch points

Most switch points, especially those located in stations and marshaling yards, are equipped with a position indicator (Signal 31), which is directly connected to the points operation mechanism. When the points are set to the through track, it displays an orange rectangle to the facing-point movements and a white rectangle to trailing-point movements. When the points are set to the diverging route, the indicator displays a diagonal arrow to the facing-point movements and a white circle to the trailing-point movements.

Athens Metro signalling

Athens metro line

Athens-Piraeus Railway Company, the predecessor of EIS (

The line between Piraeus and Omonoia Square was divided into six blocks. Details of the design and operation of the signals, the points, and the interlocking survive in Section D of the contract between the Greek Government and the railway company.[4] The system became operational in 1904.^[5]

In 1924 the new company "Hellenic Electric Railways" signed a new contract with Siemens & Halske to renovate the signalling system. The semaphores were replaced with colour light signals and electrical interlocking.

Most signals are "main signals" with two aspects (red and green). There are also a few two-aspect (yellow and green) distant signals, in locations where the main signal is not visible from a reasonable distance. If the points at a junction are set to a diverging route, this is indicated by a special "junction signal", a white diagonal line on black background. Junction signals are usually colocated with main signals, although there are quite a few stand-alone ones.

Main signals and junction signals are tagged with a number identity. Distant signals are tagged with the same number as the corresponding main signal, preceded by "Vs" (German: Vorsignal).

A new modernization programme began in 1982, still using mainly two-aspect colour light signals. Gradually the signalling system was adapted to central control from a power signal box next to

Signal	Meaning	Next signal	Semaphore equivalent	Notes
	STOP
	PROCEED
	CAUTION	STOP		Displayed by a small number of distant signals at locations with poor visibility.
	PROCEED	PROCEED		When displayed by a distant signal.
				Junction signal. When illuminated indicates that points are set to a diverging route.

A VHF/FM simplex radio system, which operated on 161.325 and 161.375 MHz, was installed in stations and driving cabs in 1985. It was replaced with a UHF/FM repeater operating on 418.575 MHz in 2004. This system was supplemented with a TETRA system in 2004. However, radio is rarely used for train control under normal operating conditions.[10]

Signalling on the lines

Points are protected by two-aspect color light signals, designated as "switch point indicators". Initially these signals display either a white or a red light. Recently the white aspect was replaced with a green aspect.

STOP	GO

Signals are tagged with an identity which consists of a three-letter code denoting the station and a number (for example "ΣΥΝ 11").

Initially, stations and driving cabs were equipped with UHF/FM radios operating on 8 simplex channels between 418.6 and 418.775 MHz, but these were replaced with TETRA radios in 2004.^[12]

Athens Tram signalling

At level crossings Athens Tram uses special light signals which are coordinated with road traffic lights. The signals are quite different from regular rail signals, in order to avoid confusion with adjacent road traffic lights. At some locations green wave signalling has been established, giving priority to approaching trams over road vehicles.

STOP	CAUTION	GO

All Athens Tram driving cabs are equipped with