Untitled - Adif

583.3.3. SAFETY, TRAFFIC CONTROLAND COMMUNICATIONSSYSTEMS3.3.3.1. SIGNALLING SYSTEMS:BLOCK SYSTEMSThe ADIF Managed Network is generallyequipped with signalling and block systemsusing diverse technology, the tendency beingto use electronic interlockings with centralisedremote control at Control Centres (CC).The most frequent block systems are listedbelow:• Automatic Control Block System (BCA)In this block system, the safety distance ismaintained by indicating a speed limit, atarget distance and a target speed in thedriver’s cab, there being various systemson the ADIF Managed Network. Later on,in the section corresponding to safetysystems, the different systems availableon the ADIF Managed Network will beoutlined.• Wayside Block System (BSL)In this block system, the safety distancebetween trains is ensured by trains respectingthe signals.• Automatic Release Block System (BLA)This block system generally has one blocksection between stations, which is protectedby signals in a similar way to the AutomaticBlock system.Depending on the signalling and tracksideconditions, there are several distinct types ofAutomatic Release Block System, similar tothe Automatic Block system.• Automatic Block System (BA)This block system generally has intermediateblock sections between stations, which areautomatically protected by signals.Depending on the signalling and tracksideconditions, there are several distinct types ofAutomatic Block System;• Single Track Automatic Block System(BAU)• Double Track Automatic Block System(BAD)Only automatic signal sequences existin this category for each track and intheir normal running directions.• Wrong Way Automatic Block System(BAB)In this type, traffic on double or multipletracks may run on either track and ineither direction.• Radio Traffic Control (CCR)This block system, used on lines with littletraffic, is ensured by means of the RTCManager being permanently informed aboutthe situation of trains in the sections, aboutauthorisation given to drivers and train arrivalnotices.