A point machine (PM) is used to move a railway track to divert trains onto a desired track. The Miro PCM-Electric (PCM-E) is a system designed to monitor the performance of a PM. See Fig. 1.
An AC single phase or DC motor drives the mechanism that moves the rails. See Fig. 2. Once the rails have reached the desired position, the motor stops. The PCM-E continuously measures the voltage and current of the motor and derives performance metrics.
A reference operation is determined after the PCM-E undergoes a thirty-operation training phase. Every subsequent operation is then compared to the reference operation and is classified as ‘Good’, ‘Possible Issue’ or ‘Critical’ to indicate the severity of the operation. The user can configure the system to send alerts and alarms, based on the severity level.
The PCM-E provides real-time insights into point operations, detects impending failures and notifies maintenance crews via emails or SCADA alerts. This enables proactive remedial action to be taken, before a catastrophic failure causes disruption of services, impacting the rail network and customers. This results in improved reliability, cost savings, and increased customer goodwill.
The metrics captured by the PCM-E allows network operators to transition from a periodic based maintenance to condition based maintenance, not only reducing operational costs, but also helping operators manage track access and downtime.
A proprietary database solution, AsMoSys (Asset Monitoring System) is used to import, view and manage PCM data, including emailing notifications.
This case study illustrates how the PCM-E helped identify a PM detection circuit failure, allowing prompt repair and normalisation of rail services.
On 28th September 2022 07:19, the PCM-E at Site 809 detected a “Lack of Operation” Event. A ‘Lack of operation’ may occur when the PCM detects Voltage but there is no operating current. This event results in a ‘Critical” classification. See Figure 3 below.
Figure – PCM-E Point operation Event List at 28-09-2022 07:19
Figure 4 shows the multi-parameter capture for the operation. The multi-parameter captures Voltage, Current, Power and Power Factor graphs for a 10 second period, allowing for more insights into what is occurring beyond the point operation.
Figure – PCM-E Point operation multi-parameter Capture at 28-09-2022 07:19
The graph in Figure 4 shows the point operation at 07:19:37 completed successfully. A few seconds later, the voltage is switched on again for the Normal side. Investigations revealed the detection circuit failed to detect the completion of the point operation and therefore an attempt was made to move the point again in the same direction. A loose terminal wire in the detection circuit of the point machine was identified as the cause for this failure. Figure 5 below shows the point operation at 10:20 following the repair.
Figure – PCM-E Point operation multi-parameter Capture at 28-09-2022 10:20
This case study illustrates how the PCM-E alerted railway maintenance staff and helped identify the faulty detection circuit, allowing prompt repair and normalising of the rail network.
CHK Power Quality Pty Ltd
Unit 1, 3 Tollis place
NSW 2147
Australia