OLE StAT was developed in collaboration with Atkins, UK using high-frequency wire height and stagger data gathered by train-borne measurements from a variety of systems, operated by service trains and maintenance units across the world.
A peak fitting strategy, inspired by X-Ray diffraction, analyses the contact wire inflection as a result of the droppers lifting the wire at specific along track positions as specified by the system design parameters. The result is an unprecedented ability to resolve poor performing OCS locations by identifying the exact location and nature of the defect. As the exact mechanical, installation or manufacturing source of the OCS defect is determined and characterised as part of the analysis, a comprehensive resolution of the issue enables a fast and direct rectification action to be reported to the infrastructure maintenance crews. Additionally, the proposed interventions recognise the as-fitted span parameters and accommodate for all vertical and along track tolerances of the installed system. As a result, on-site inspection is minimised enabling swift targeted interventions with excellent rateability and traceability.
We solve the interface problem at the source by direct intervention to the OCS system
What is unique to OLE StAT:
- Enable, prioritise and instruct targeted wiring adjustments that directly improve the dynamic interface performance (mechanical interaction of the asset with the pantograph)
- Systematic approach to construction assurance based on train-borne data, which will enable faster sign-off for route testing and third-party assurance evidence to the installation quality
- Gain direct insight to dropper compliance which improves high-speed operation and accelerates on-site interventions. The mapping can be specified to progress in tandem with the installation which will eliminate post completion interventions
- Map the entire network and hand-over to the Route Asset Manager to be used as the baseline for Asset Condition Monitoring strategy and predictive maintenance.
What are typical route causes which affect interface performance and can be identified and rectified using OLE StAT?
- wire ‘kink’: Contact wire bent out of shape during manufacturing or installation process. Sometimes the same effect can be produced by local rail track subsiding, but the difference can usually be picked up by the analysis as it likely affects stagger and wire profile channels differently.
Figure 1: Contact Wire ‘Kink’ and Z-dropper analysed static wire profile using OLE StAT with the resulting impact to the interface contact force collected by MENTOR.
- wire tensions: wire tensions might vary within individual wire runs having an effect to wire presag shape and wave propagation speeds at the interface with the pantograph. The latter effect is more significant at speeds of >100mph
- dropper along track location: A system required ±0.5m tolerance is required in the UKMS design manual (add reference) and affected by a number of factors such as ‘actual’ vs design specified span length and dropper installation strategy. For instance, in a 51m actual span that was designed as a 50m span with the distance from the support to the first dropper specified at 5m, the last dropper distance to the end of the span will be 6m. Effectively, the result of this is a non-symmetric contact wire profile and non-uniform load distribution across the droppers.
- dropper lengths: Dropper lengths are affected by the manufacturing tolerances and position of the dropper relative to the messenger wire catenary profile. The manufacturing tolerances are normally kept under 5mm and have a minor effect to the static wire profile. The position of the dropper along the span is significantly affected by the catenary wire shape. An ideal dropper at 15m from the start of the span is 30mm longer than required when it is located 16m from the span start. The same phenomenon occurs when catenary support height variation results in the low point of the catenary wire shifting away from the centre of the span.
- in-line insulator components: insulator components such as Section Insulators and Neutral Sections are necessary to enable electrical isolations and enable operation (electrical distribution) and maintenance of the system. These components are spliced in and are usually heavier and stiffer than the wiring they replace. As a result ‘hard spots’ on the system interface are regularly encountered in part of the systems where such components are installed.
- crossing wires: Cross-overs are quite important component that enable the rail network operation and usually are affected by the added weight of section insulators and absolute height variation between adjacent tracks which often results in the crossing wire (merging wire) sagging at a lower height in relation to the main wire which can result in poor performance or significant de-wirement incidents.
- additional wires added for electrical: Jumper cables and others are often installed connecting the CW to the MW or other switching components in the overhead system. These often introduce ‘hard-spots’ to the interface if they are not installed correctly.
- additional wires added for system safety: Z-dropper arrangements are often introduced in the near Mid-Point Anchor (MPA) locations. The added weight, wire pretension and constraining of the droppers that are crossing with the Z-dropper cable can sometimes result in excessive hogging (‘presag’ deficiency) in the middles of the span. When combined with the wire splicing arrangements onto the contact wire it often impacts the dynamic interface performance.
- wire height min/max limits: The height limits might not affect the mechanical interface performance, but they might result in pantograph Automatic Dropper Device (ADD) activation when maximum height thresholds are breached or foul the train gauge if the wire is suspended too low.
- wire stagger min max limits: The stagger limits might not affect the mechanical interface performance, but they might result in pantograph carbon entanglement and result in significant de-wirement incidents.
Asset level condition monitoring Summary
OLE StAT additionally offers a high-level dashboard summary of the wire analysis introducing a ‘traffic light’ system based on the specified installation or maintenance thresholds. The OLE StAT dashboard output in enables a high level system conformance check which enables a comprehensive schedule for snagging or maintenance interventions to be passed on to the installer/maintainer. In the case of OVH Wizard acquisition where both messenger and contact wires are mapped specific dropper lengths can be identified. In the case of NMT data where the contact wire is only available relative length corrections can be assigned to individual droppers within individual spans.
Figure 2: ‘Traffic Light’ dashboard OLE StAT output to enable high level system conformance checking for every span.
Single Rod Arthur Flurry Neutral Sections are capable of operation up to 125mph, but they are acknowledged as rigid components with separate allowances in the applicable interface performance criteria specified by the NTSN Section 4.2.12. The static wire profilometry data are collected by NMT NR service train and the analysis is carried out by OLE StAT. The dynamic interface data are collected by the MENTOR NR service train using an Brecknell Willis (BW) HSA pantograph instrumented by DBST. The NMT data enabled to an up-to-date view of the system following on-site adjustments post the original installation. It is noted that a slight ‘hogging’ can be observed in both directions at the Neutral Section supports. The overall forces collected at 100mph are within acceptable levels with the Down Fast direction likely to incur local loss of contact at higher speeds or multiple pantograph formations (Fmin < 0N, NQ[%] > 0).
Figure 3: Arthur Flury Single Rod Neutral Section installation on the Down Fast and Up Fast direction analysed static wire profile using OLE StAT with the resulting impact to the interface contact force collected by MENTOR.
