1. The track circuits are considered as the vital component of signaling system to achieve safety of train operations. Various Accident Enquiry Committees have recommended to bring more and more tracks under track circuiting to safeguard against reception of trains on occupied lines. The track circuiting could not achieved desired progress die to virtual scarcity of wooden sleepers, prohibitive costs and environmental consciousness in the country and the world at large. Availability of concrete sleepers have solved the problem to some extent but track circuiting on loop lines, points and crossings still suffers for want of adequate supply and insertion of concrete sleepers. 2. Axle counters were developed as a substitute for track circuiting. Initially axle counters were imported from Germany to gain experience and to evaluate their suitability for adoption on Indian Railways. Having gained acceptability for introduction on a wide scale on Indian Railways, it was considered to take up indigenous development of axle counters which was taken up in collaboration with IIT, Delhi and DOE. Two models of axle counters known as single entry/exit axle counter were emerged and after extensive laboratory and field trials under various conditions, the design was finalized and commercialized through private sector as well as public sector.
Based on the feed back from filed, a new axle counter has been developed by RDSO, known as “UNIVERSAL AXLE COUNTER”.
The advantages of Axle counter over a conventional track circuit are that: i) It does not require wooden sleepers (where concrete sleepers are not available) except for short track circuits to suppress the counts due to movement of insulated trollies. ii) An axle counter system can cover a very long section up to 15 km as compared to 750 mts of maximum length of operation of conventional track circuit. iii) It does not get affected either by flooding of track or poor maintenance of track unlike the track circuit, which is highly susceptible to these conditions. iv) It does not require insulating joints, thus, rails can be continuously welded. This reduces track maintenance cost, lower wear and tear of tracks and vehicles and to increase traveling comfort.
1. Axle counters have been finding more and more uses on modern safety signaling systems in railways.
These are being used presently for the following :
i) Monitoring of berthing tracks in station areas and yards (drawing no.1005985A4). ii) Monitoring of Point zones in station areas and yards (drawing no.1005986A4 & 1005987A4). iii) Automatic Signaling systems using axle counters (drawing no.1005988A4). iv) Block working through axle counters using multiplexers with cable are radio communication (18GHz) (drawing no.1005989A4 & 1005990A4). v) Level-crossing warning system using axle counter (drawing no.1005991A4).
2. BRIEF DESCRIPTION :
it is an electronic device consisting of :-
i) A set of track inductors fitted at the entrance of a length of a track which “COUNTS IN” the number of axles passing over them. ii) Another set of track inductors fitted at the exit of the length of track which “COUNTS OUT” the number of axles passing over them. iii) An evaluator which registers “COUNTS IN” and “COUNTS OUT” and ‘CLEAR’ the line, if two are equal and shows “ACCUPIED” if the two counts are defferent. iv) The principal of counting axles is described below (drawing no.1005993A4). The magnetic flux generated by the 5 khz current following in the transmitting coil induces a voltage in the receiver coil. These coils are fixed opposite to each either side of running rail. When a wheel passes between these two coils, the magnetic flux path gets disturbed and the induced voltage in the...