Remote Condition Monitoring of Signal Assets at CSX William Larson, CSX 500 Water Street, Jacksonville FL 32202 USA, [email protected]Joe Denny, TekTracking, LLC, 10 Norbrook Road, Fairport NY 14450 USA, [email protected]Nick Wright PhD AMIRSE, MPEC Technology Ltd, 6 Pinnacle Way, Pride Park, Derby, DE24 8ZS, United Kingdom, [email protected]NUMBER OF WORDS: 2093 ABSTRACT Remote condition monitoring can enhance traditional railroad maintenance regimes and reduce the occurrence of signalling failures. Monitoring the performance of track switches is particularly attractive as track switch failures can be especially disruptive. This paper presents the experience of CSX, a Class 1 railroad in North America, who have been an early adopter of remote condition monitoring technology for track switches. The paper discusses the current stage of the railroad’s remote condition monitoring roll-out, its objectives, and how it is used. A description of the condition monitoring technology is given together with some examples of the analytics and data it provides. OVERVIEW OF REMOTE CONDITION MONITORING AT CSX In 2013 CSX, a Class 1 freight railroad operating in the United States began to explore the possibility of using remote condition monitoring (RCM) to enhance their track switch maintenance regime. CSX conducted a limited trial of RCM equipment from three different suppliers in 2014-15, before ultimately selecting the hardware and software solution manufactured by MPEC Technology. A wider trial roll out of the technology began in 2017. Currently, CSX remotely monitors 298 critical track switches across the Albany and Baltimore Divisions. These switches are generally located between Rochester NY and Albany NY, along the I- 95 corridor, and west from Baltimore MD past Cumberland MD. Switch alarms are presented in a dashboard format which is monitored by the local Signal Managers and responsible Signal Maintainers. Figure 1 - Map of CSX switch monitoring installations The remote condition monitoring scheme at CSX has two main components: SA380 Series dataloggers and Centrix, an RCM analytics software package. The SA380 dataloggers are trackside IoT devices which can collect both analog signals and digital data from a variety of sensors using standard 4-20mA, RS485 or 0-10V interfaces. This sensor data is then transmitted to the remote analytics platform via either an internal GSM modem or via Ethernet. For track switch monitoring at
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Remote Condition Monitoring of Signal Assets at CSX William Larson, CSX 500 Water Street, Jacksonville FL 32202 USA, [email protected] Joe Denny, TekTracking, LLC, 10 Norbrook Road, Fairport NY 14450 USA, [email protected] Nick Wright PhD AMIRSE, MPEC Technology Ltd, 6 Pinnacle Way, Pride Park, Derby, DE24 8ZS, United Kingdom, [email protected] NUMBER OF WORDS: 2093 ABSTRACT Remote condition monitoring can enhance traditional railroad maintenance regimes and reduce the occurrence of signalling failures. Monitoring the performance of track switches is particularly attractive as track switch failures can be especially disruptive. This paper presents the experience of CSX, a Class 1 railroad in North America, who have been an early adopter of remote condition monitoring technology for track switches. The paper discusses the current stage of the railroad’s remote condition monitoring roll-out, its objectives, and how it is used. A description of the condition monitoring technology is given together with some examples of the analytics and data it provides. OVERVIEW OF REMOTE CONDITION MONITORING AT CSX In 2013 CSX, a Class 1 freight railroad operating in the United States began to explore the possibility of using remote condition monitoring (RCM) to enhance their track switch maintenance regime. CSX conducted a limited trial of RCM equipment from three different suppliers in 2014-15, before ultimately selecting the hardware and software solution manufactured by MPEC Technology. A wider trial roll out of the technology began in 2017. Currently, CSX remotely monitors 298 critical track switches across the Albany and Baltimore Divisions. These switches are generally located between Rochester NY and Albany NY, along the I-95 corridor, and west from Baltimore MD past Cumberland MD. Switch alarms are presented in a dashboard format which is monitored by the local Signal Managers and responsible Signal Maintainers.
Figure 1 - Map of CSX switch monitoring installations
The remote condition monitoring scheme at CSX has two main components: SA380 Series dataloggers and Centrix, an RCM analytics software package. The SA380 dataloggers are trackside IoT devices which can collect both analog signals and digital data from a variety of sensors using standard 4-20mA, RS485 or 0-10V interfaces. This sensor data is then transmitted to the remote analytics platform via either an internal GSM modem or via Ethernet. For track switch monitoring at
CSX, contactless Hall-effect current transducers are used to monitor switch motor current draw in a non-invasive manner. Up to ten power switch machines can be monitored from a single SA-380 data logger, and 8 loggers can be networked together within the same interlocking. Figure 2 below shows an example datalogging installation in a lab environment (the black device on the left is the data logger).
Figure 2 - Demonstration installation of an SA-380TX datalogger
This track switch data is sent to Centrix (typically within a few seconds after a switch has operated), and it is checked for abnormal properties (i.e. excessive current draw, abnormal switch movement duration). When an abnormal switch movement is detected, Centrix raises an alarm providing dashboard indication and an email to the responsible maintenance team. Machine learning and statistical tools are used to calibrate this alarm system and label data of interest. Centrix can also be used to review and replay historical data, generate reports, and provide automated statistical analysis of track switch performance over time. The motivation and philosophy of this RCM system (and most others) is to allow engineering maintenance teams to move away from scheduled and reactive maintenance, to a pro-active condition-based maintenance regime. This allows maintenance work to be carried out in response to the dynamic state (or health) of trackside and signalling assets, which is in most cases more efficient in terms of expenditure and labor and more importantly reduction of train delay. OBJECTIVES CSX has an internal metric called Train Delay Index (TDI), used to approximate delays due to system failures recorded in the incident reporting system. TDI is calculated using the sum of:
𝑓𝑓(α, β, γ) = α ∗ β ∗ γ Where:
- α is the time between opening and closing an incident in the CSX reporting system. - β is the estimated average number of trains passing through affected area per hour, based on
the previous 13 weeks of operation.
- γ is a scaling factor, based on the proportion of one hour an individual service would likely be delayed.
Use of the TDI metric highlighted that while some equipment failures, for example crossings, are more numerous, switch failures have a greater impact in terms of train delay and therefore have a disproportionate operational impact. The following table shows TDI attribution for switches and crossings for CSX nationally, by way of illustration.
Table 1 - TDI for CSX nationally in 2017 and 2018
The objective of the remote condition monitoring scheme was to reduce the number and severity of track switch failures, by identifying unusual switch performance, and scheduling preventative maintenance interventions to mitigate incipient failures. A review of historical failure data showed that between approximately 40% and 55% of track switch maintenance interventions resulted in adjustment or replacement of failed components. As such, it was felt that a 25% reduction in Train Delay (TDI) could be achieved with judicious use of RCM. In addition to the headline benefit of reducing train delays, the following secondary objectives were also identified:
1) More efficient use of staff hours. A reduction in unplanned maintenance interventions results in fewer interruptions of scheduled activities, reduced travel time, and reduced time on site overall.
2) Reduction in overtime and availability of Hours of Service (HOS) employees. When RCM tools can provide warning of incipient faults, corrective maintenance activities can be scheduled during normal working hours, reducing the need for call outs during night hours. This has additional positive safety implications.
3) Reduced material cost from repair of catastrophic failures.
4) Improved record keeping and analysis of historical data. Comparison of real-time and historical data allows for post maintenance verification of asset performance. Furthermore, images and tables can be appended to fault reports. These can be cross-referenced and used to assist in future fault investigations.
A MODIFIED MAINTENANCE REGIME In day to day usage Centrix provides the following facilities to enable RCM:
Incidents TDI2017
Crossing 3661 917Switch 2968 5182
2018Crossing 3488 937Switch 3276 5996
Real-time Alerts And Classification Of Data When a track switch begins to develop a fault, we can often see changes in motor current draw. For example, consider the motor current measurements (capture traces) shown below in Figure 3. Motor current draw is shown on the Y-axis and time since the motor began to operate is shown on the X-axis.
Figure 3 - Motor current capture traces over four days showing evidence of a developing fault
Five motor current capture traces are overlaid for comparison. In each trace we can see three distinct phases: The inrush phase at the start of the trace where the motor is first turned on and gets up to speed. The second, mostly flat region where the switch assembly is in motion but before the switch blades begin their traverse. The final region where the switch blades are moving and the motor is draws more current. If we compare the capture traces recorded on March 8th and 10th with those recorded on March 6th, we can see that the motor is drawing increased current while the switch blades are moving, and that the overall operation of the switch is slower. Intuitively we understand that this is because the motor is having to produce more torque to move the switch blade assembly. When this occurs, and when we can see the amount of required torque is increasing, we can infer that the switch could be developing a problem. In the example above, this could be poor lubrication, debris fouling the mechanism, shifting ballast changing the geometry of the assembly, and so on. Capture traces are affected by fault conditions in various ways. Where a problem affects just one part of a movement (i.e. a “tight lock” fault), just the corresponding portion of the capture trace will be affected, for example appearing as an anomalous peak. Where the problem affects the entire switch operation the entire trace is affected. For example, a switch motor with worn commutation brushes will result in capture traces where a saw-tooth pattern appears to be superimposed on top of the trace. With a combination of experience and knowledge of the history of a given machine, in many cases it is possible to diagnose the likely cause of the problem prior to a manual inspection. In the chart below, Figure 4, we can see two capture traces. The trace in blue shows a typical switch movement. The trace in red shows a failed movement, where the switch failed to unlock causing the switch motor to stall.
Figure 4 - Two capture traces. A normal switch operation is shown in blue, a failed operation shown in
red
We can see here that the motor stall current is approximately 5 Amps. We therefore know that if the peak motor current (excluding the motor inrush current) is increasing over time and approaching 5 Amps, the switch is in danger of failing, and corrective action should be taken. Centrix analyzes capture traces as they are received and alarms can be configured. When an alarm is raised an automated email is sent to the engineer(s) responsible for the related asset, and a summary sheet describing the alarm is generated. By default, Centrix will create alarms for track switches that are triggered on the following conditions: Excessive average current draw, peak current (excluding motor inrush current), and high swing time. These alarms are configured using the “alarm wizard” facility which calculates appropriate alarms thresholds automatically via statistical analysis of historical data. In addition to alarms, traces which show evidence of maintenance, failures resulting in the switch motor stalling, or sensor failure are automatically tagged. Centrix uses a Convolutional Neural Network to identify these traces based on their profile or shape. Finally, a dashboard can be configured which shows the real-time alarm status and performance of any monitored asset. Typically, this dashboard is shown on a large format display in a shared workspace (i.e. maintenance engineering team office). At CSX, alarms and traces which have been flagged as anomalous are reviewed as they are received by local maintenance teams. Collections of data and alarms are also periodically reviewed by the headquarters technology team. The decision to carry out maintenance interventions based on a given alarm is made by local team members. All alarm thresholds at CSX are recalibrated once per week.
Figure 5 - An alarm summary page in Centrix
Review Of Historical Asset Performance And Generating Reports Track switch data sent to Centrix is stored indefinitely in a back-end database, so a historical record is maintained. When examining the performance of a given track switch, it is often useful to compare current and historical data. For example, the chart below shows the trend of average current draw per movement for two ends of a switch.
Figure 6 - Performance trends of a track switch over a three-month period. Note the abnormal current
draw in January and February
This switch failed in January and February. In both cases the increased and abnormal current draw trend around those times provided advance warning. In addition to periodic reviews of current draw trends (carried out daily at CSX), it is particularly useful to check the performance of track switches after maintenance work has been carried out. For example, after tamping, the average current draw of track switches should be checked to ensure that any shifted ties or ballast have not caused poor switch performance. Centrix can also generate reports based on historical data that would otherwise be difficult or time consuming to obtain. For example, the precise number of switch operations for a given time period can be obtained, and the number of successful versus unsuccessful throws enumerated.
FUTURE CONSIDERATIONS Centrix is under continuous development. Recent advances in machine learning techniques have provided new means of identifying patterns and trends in large datasets like those being collected by CSX. Future updates will be focused on differential treatment of track switches with different layouts and geometry, using new analytical tools to find correlations between track switch data and specific faults, and analytics which use data collected from a combination of sources (i.e. based on both track circuit and switch data together). In addition to technical enhancements, continued focus on the day to day workflow with Centrix and datalogging devices is necessary. RCM tools are not a magic bullet. They are only effective if engineers can successfully integrate them into their daily work routine. Proper training, clear user interfaces, and understanding the relevance of data and analytics is essential.
REMOTE CONDITION MONITORINGOF SIGNAL ASSETS AT CSX
REMOTE CONDITION MONITORING OF SIGNAL ASSETS AT CSXMPEC Technology Ltd (Derby UK)
TekTracking (Rochester NY)
CSX (Jacksonville, FL)
OVERVIEW OF CSX RCM JOURNEY
• GOAL: REDUCE TRAIN DELAYS DUE TO SWITCH FAILURES• 2013: EXPLORATION PHASE• 2014-2015: LIMITED TRIAL WITH 3 VENDORS• 2016-PRESENT: PRODUCTION ROLLOUT WITH MPEC/TEKTRACKING
• FIRST PHASE – ALBANY DIVISION• SECOND PHASE – BALTIMORE DIVISION• TOTAL 298 TRACK SWITCHES MONITORED 24/7/365
RCM SCHEME DEPLOYED AT CSX
• SA-380TX DATALOGGER• PROVIDES DATA COLLECTION FROM DEPLOYED SENSORS• MEASURE CURRENT, VOLTAGE, TEMPERATURE, DIGITAL EVENTS• CSX PTC NETWORK: PUSHES FIELD DATA TO CENTRIX ANALYTICS• MPEC’S CENTRIX: DATA ANALYTICS AND VISUALIZATION PLATFORM• CENTRIX: ANALYZES FIELD DATA AND GENERATES ALARMS
CENTRIX PREDICTS INTERLOCKING FAILURES
MPEC SA-380TX EVENT RECORDER• MONITOR UP TO 10 POWER SWITCH MOTORS PER RECORDER
MPEC SA-380TX EVENT RECORDER
• USE NON-ENVASIVE SENSORS TO MEASURE KEY ATTRIBUTES• BASELINE MEASUREMENT IS A NORMAL OPERATION• ALL SUBSEQUENT OPERATIONS ARE COMPARED TO BASELINE• DATA IS STORED IN THE EVENT RECORDER MEMORY• DATA IS ALSO SENT TO CENTRIX FOR ANALYSIS
CENTRIX - ANALYTICS & VISUALIZATION
CENTRIX - ANALYTICS & VISUALIZATION
CSX RCM OBJECTIVE – REDUCE TRAIN DELAYS
• CSX TRAIN DELAY INDEX – TDI• TDI – CROSSING VS. INTERLOCKING FAILURE• HISTORICAL DATA – 40-55% MAINTENANCE EVENTS RESULT
IN SWITCH COMPONENT ADJUSTMENT/REPLACEMENT• GOAL – ACHIEVE 25% TDI REDUCTION WITH RCM
