Spanish Railway Communications System (Tren-Tierra)

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Linchys

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Hello. Today I am going to talk about the radio communications system used in the spanish railway line.

The Tren-Tierra (Train-Land) system was developed by AEG (later ALCATEL) at the request of the railway state company RENFE (Red Nacional de Ferrocarriles Españoles), it was implemented in 1983 and since then installed on the entire conventional railway line (not high speed lines).

This is an analog radio communications system, and it is structured into three types of stations:

- Central station: Located in the command post, where the circulation agent who can send orders to the trains is located.

- Fixed station: They are strategically placed along the railway line, so that coverage is complete.

- Mobile station: Located on board the train or in portable equipment, for communication between the driver and the command post. It communicates via radio with the fixed position that allows greater signal intensity and quality.

Communication is always carried out between the mobile station and the central station through the fixed stations, connected via radio to the mobile station and by anu kind of system (wired o wireless) to the central station.

Automatic switching is available, therefore as the train advances it automatically changes its fixed position without interrupting communication.

Communications between the train and the command post can be of two types: through predefined written messages (status) or directly through voice calls.

It only allows one communication on each channel at the same time, giving priority to emergency calls.

Each train that has a mobile station has a Train-Land panel with a screen where written messages are received and with several buttons that allow the system to be operated.

The railway network is divided into different zones, each of which has its own system command post. Each zone has a different communications channel than the adjacent zones to prevent messages from different zones from overlapping.

The frequencies reserved for the Train-Land system are the following:

447,550 TX Fixed Station frecuency
447,600 TX Fixed Station frecuency
447,650 TX Fixed Station frecuency
457,600 RX Fixed Station frecuency

447,650 TX Fixed Station frecuency
447,700 TX Fixed Station frecuency
447,750 TX Fixed Station frecuency
457,700 RX Fixed Station frecuency

447,850 TX Fixed Station frecuency
447,900 TX Fixed Station frecuency
447,950 TX Fixed Station frecuency
457,900 RX Fixed Station frecuency

448,450 TX Fixed Station frecuency
448,500 TX Fixed Station frecuency
448,550 TX Fixed Station frecuency
458,500 RX Fixed Station frecuency

448,325 TX Fixed Station frecuency
448,375 TX Fixed Station frecuency
448,425 TX Fixed Station frecuency
458,375 RX Fixed Station frecuency

448,275 TX Fixed Station frecuency
448,325 TX Fixed Station frecuency
448,375 TX Fixed Station frecuency
458,325 RX Fixed Station frecuency

448,550 TX Fixed Station frecuency
448,600 TX Fixed Station frecuency
448,650 TX Fixed Station frecuency
458,600 RX Fixed Station frecuency


There are also several simplex analog frequencies, reserved for direct short-range communications, such as during maneuvers or for communications between the command post and the train driver in the vicinity of the station. These are the following:

457.600 MHz Channel 1
457.700 MHz Channel 2
457.825 MHz Channel 3
457.900 MHz Channel 4
458.325 MHz Channel 5
458.375 MHz Channel 6
458.500 MHz Channel 7
458.600 MHz Channel 8

This is my little explanation of the system.

Greetings!!
 

wa8pyr

Retired and playing radio whenever I want.
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Very nice description, thanks!

Nice to see that not everybody in Europe is jumping on the Tetra or GSM bandwagons, and sticking with reliable old analog.
 

Linchys

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Very nice description, thanks!

Nice to see that not everybody in Europe is jumping on the Tetra or GSM bandwagons, and sticking with reliable old analog.
Hi wa8pyr,

Here in Spain, GSM-R technology is used on high-speed railway lines and has also been implemented on conventional railway lines with high traffic density.

There are also several underground's networks that use the TETRA system for their voice and data communications, such as the Madrid Metro.

Greetings!!!
 

cbehr91

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Interesting. I assumed most rail communication in within the EU was GSM-R, and thus not listenable by the general public.
 

EI9BAB

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Ireland is moving from analogue to GSM-R for rail systems. Unencrypted Tetra is currently used for the "Luas" Tram system in Dublin.
 

Ubbe

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Stockholm, Sweden
Automatic switching is available, therefore as the train advances it automatically changes its fixed position without interrupting communication.

The railway network is divided into different zones, each of which has its own system command post. Each zone has a different communications channel than the adjacent zones to prevent messages from different zones from overlapping.

447,550 TX Fixed Station frecuency
447,600 TX Fixed Station frecuency
447,650 TX Fixed Station frecuency
457,600 RX Fixed Station frecuency
Do you have any more info how the train scan between those three frequencies, is it just by a carrier squelch like in a scanner? Are those three frequencies transmitting only when dispatcher starts to talk, how does the train initiate a call request, some call tone or a sequential tones that indicates the train ID?

/Ubbe
 

EI9BAB

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Messages
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When operating Mode A, one receiver shall be on the actual best receiving channel for the group while the second receiver shall always scan for a better channel. Switch over between the receivers shall be 200ms (+/- 20%).

Have a Google for UIC 751-3 add that should provide you with a lot of the information you are looking for.
 
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