Axle Counter Block System (ACBS) is a modular electronic signalling system for movement of trains in a Block Section. ACBS is designed with TTL & CMOS IC Circuits suitably interfaced with trackside equipment and relays. ACBS is the prewired system and can be easily installed and maintained by existing staff. The technology used in the ACBS gives a higher level of safety than the conventional Block working through Block instruments. However, the electronic design ensures that the present skills of engineering, operating and maintenance staff can continue to be used.

System Performance :

ACBS consists of Axle Counters for monitoring the block section, Multiplexers for exchange of Block Status information between stations, SM's panel for control and operation of Block. The system controls the Last Stop Signal (LSS) of each Up and Down Line of Despatch Station for Entry of train into the Block Section.

Axle Counter :

Axle Counter based Block Proving System for Railway Signalling

Axle Counter at the receiving Station detects the presence of a train while passing the LSS Signal & "Counts In" the number of Axles of train entering the Block Section. While train is leaving the Block Section at Home Signal of receiving Station, the same Axle Counter "Counts Out" the number of Axles of the same train. When both counts registered from train are equal in the Axle Counter, the Block Section is shown as "Free". Otherwise, the Block Section is shown as "Occupied". The status is displayed on SM's Panels of both Stations. By means of above checking the arrival of complete train into the receiving station out of the Block Section is automatically verified and the absolute Block working is achieved.

Multiplexer :

Multiplexer Transmitter sends relay information of Block status by means of FSK coded signal from one station. The receiver multiplexer receives the signal, decodes and drives repeat relays at the other station. A frame time of 145 milliseconds, consisting of all relay informations is generated and repeatedly transmitted from one station to another. In 1 second each relay is repeated 7 times at the next station. The change of relay information is acted accordingly.

SM's Panel :

Station Master's (SM) Panel Controls, indicates and provides the information for smooth and safe operations of trains in the Block Section. It also features train entry relay logic interlocking circuits provided for despatch and reception of train into the Block Section make the system safer for each train movement.

FEATURES :

• Electronic Signalling System for block working
• Modular Design of equipment and easy to install
• Eliminates the need of Last Vehicle (LV) check
• Checks complete arrival of train and prevents mid block section accidents
• Line clear by pressing Push Buttons on SM's Panel
• Automatic working of 'Train on line' and 'line closed'
• MTBF of the order of 106 hour
• Comprehensive Diagnostics
• Proven & fail safe design
• Working on one and half PET quad cable
• Compatible with current and future signalling systems