A fresh approach to an ongoing problem

The Asia Pacific Rail Research and Development Program has produced a unique approach to the optimisation of DC track circuitry. APR’s system operates with unprecedented accuracy, accommodating specific site circumstances, achieving the maximum immunity to both right side and wrong side failure.

The established technique of adjusting DC track circuit configurations in the field under varying environmental conditions is fundamentally flawed. Single adjustments will only respond to the isolated circumstances of one test and multiple tests are costly and time consuming. APR’s DC TrackCircuit simulates a track circuit based on a range of variable system parameters. From this single simulation optimum adjustments can be determined in accordance with defined variation limits.

Irrespective of track circuit conditions, the user can implement these parameters, confident in the knowledge that current operations will be guaranteed for all variations within the predefined limits.

For more information or a demonstration please contact our office.

Variable limits providing numerous outcomes

Simulation, within a range of client provided variables, will identify potential problems including a poorly regulated power supply, high resistance leads and low track ballast resistance. In addition, allowable limits can be specified for track ballast resistance, supply voltage variations and shunt resistance. Alternative configuration tests can also be applied to ascertain if acceptable alternatives are possible and at what expense.

Using simulation, the limit conditions under which failure will occur can be calculated. Both right side failure (low voltage regulation and low ballast resistance) and wrong side failure (high voltage regulation and high ballast resistance) can be determined, providing known limits for the specified shunt resistance.

DC TrackCircuit results can also determine the test shunt resistance required to cause a track relay to release under the conditions available at the time of testing. Unlike prior testing methods, DC TrackCircuit results take advantage of the maximum discrimination between the two circuit states (occupied and clear) which are achieved when the termination resistances are made to be equal.

DC TrackCircuit analysis provides rail engineers and operators with accurate, functional data to maximise the safety and optimise the reliability of track circuitry. Please contact our office for a demonstration.

DC TrackCircuit
Simulation and Optimisation provides:

	Optimal adjustment with greatest margin against failure;
	Data which will allow track circuitry to operate reliably when climatic conditions change;
	Considerable reductions in unnecessary expenditure due to track leads as well as power supplies and converters, and;
	Advice as to which existing track circuit components may be retained or need replacement.

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