Methods to Overhead Line inspections

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himarele

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Hello everybody! I am studying the methods to control the geometrical parameters of the catenary and I have read that in my country you can measure them with a rule! It’s crazy! Is it used this ‘rule’ in your country? I know that there are also some automatic machines. Do you use them? I know there are also some automatic equipment. Do you know any of them?

Thank you very much for your help! Your opinions and explanations are be very helpful for me! ;)
 
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Philip Phlopp

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Hello everybody! I am studying the methods to control the geometrical parameters of the catenary and I have read that in my country you can measure them with a rule! It’s crazy! Is it used this ‘rule’ in your country? I know that there are also some automatic machines. Do you use them? I know there are also some automatic equipment. Do you know any of them?

Thank you very much for your help! Your opinions and explanations are be very helpful for me! ;)

The majority of OLE inspection is performed using monitoring equipment on survey trains, such as the New Measurement Train and a specialist vehicle known as MENTOR (an acronym for Mobile Electrical Network Testing, Observation and Recording, which is typically used these days to test new OLE installations).

The vehicles have specially instrumented pantographs which measure uplift force and contact wire deflection. They can record oscillations in the catenary and provide information on tensioning.

Most recording is done without using the pantograph, it's done using video cameras and pattern recognition, generating data on stagger and geometry automatically and flagging any issues. It should spot droppers and any debris in the OLE. There's some thermal monitoring if I remember correctly which looks for overheating/damaged insulators too, as we use a lot of headspan catenary where a single failed insulator will close all four tracks on a route.

In addition to checking the catenary, there's PanMon, which monitors pantographs for damage, which could in turn damage the OLE. It's pattern recognition based too, and is deployed at four sites on the West Coast Main Line (not sure if deployment has finished yet). There's an older system too, PanChex, which is force based (it's 30 years old) and PanMon will replace it.

Finally, various passenger trains record OLE through video cameras installed beside their pantographs and this is also reviewed, there's a plan to install a lightweight pantograph force monitoring system on passenger trains too, making use of a fibre optic system, but it needs to undergo trials and have a safety case approved first.

I hope that answers your questions.

PanMon - http://www.railengineer.uk/2015/12/18/pantograph-monitoring-passes-trials/ and https://www.imeche.org/news/news-article/rail-technology-reduces-risk-of-overhead-wire-damage

MENTOR - http://www.traintesting.com/Mentor.htm
NMT - http://www.traintesting.com/NMT.htm
 

Elecman

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I think the OP is referring to manual height and stagger measurements by his use of the term rule (sic).

The equipment is an insulated pole with a tee bar on top marked with dimensions from centreline and overall height. Placed on the rails and raised till the Tee bar touches the contact wire, when the height and offset of the contact wire can then be read directly.
 
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crehld

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Finally, various passenger trains record OLE through video cameras installed beside their pantographs and this is also reviewed, there's a plan to install a lightweight pantograph force monitoring system on passenger trains too, making use of a fibre optic system, but it needs to undergo trials and have a safety case approved first.

Is this why you'll occasionally see a train with bright lights on the roof pointed towards the pantograph?
 

swt_passenger

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Is this why you'll occasionally see a train with bright lights on the roof pointed towards the pantograph?

Partly. Another important reason for the new generations of EMUS having pan cameras as a matter of course is that they can be used to show after an incident if a dewirement is caused by an infrastructure fault or not.

That will probably have a financial value to the TOC, and cameras are getting cheaper all the time...
 

Bald Rick

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Partly. Another important reason for the new generations of EMUS having pan cameras as a matter of course is that they can be used to show after an incident if a dewirement is caused by an infrastructure fault or not.

That will probably have a financial value to the TOC, and cameras are getting cheaper all the time...

NXEA specified pan cams on the 379s precisely for that purpose. Although the first dewirement with Pan cam footage showed it to be the train's fault, and we'd have not worked it out without the footage. Petard and hoist.
 

Philip Phlopp

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I think the OP is referring to manual height and stagger measurements by his use of the term rule (sic).

The equipment is an insulated pole with a tee bar on top marked with dimensions from centreline and overall height. Placed on the rails and raised till the Tee bar touches the contact wire, when the height and offset of the contact wire can then be read directly.

I meant to ask about 'rule' and whether the OP was talking about that.
 

himarele

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Wow! Thank you for the information!!! I know some automatical equipments for auscultations and in fact, I am doing a study about this methods in UK and Germany.

Where are you from? Do you live in UK or Germany? (I would like to know what method is more popular in these countries: automatical equipments or... the 'rule' because so much people here in Spain love manual methods...)

Thank you again!

(Sorry for using the expression 'rule' instead of 'manual methods' I wasn't sure with the translation)
 

randyrippley

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I'm certain MENTOR was one of the test coaches in the HST/APT-P trial set I saw at speed on the WCML in around 1978 around Galgate.
Formed something like Prototype HST power car - unidentified test car (possibly Prometheus?) - APT power car - second APT power car - dynamometer car (?)- MENTOR - test car 5 (?). It was longer than the online photos of the APT test train show, and had at least four red/blue liveried test coaches

I guess MENTOR was there to check how much damage the APT pantographs were causing to the existing catenary
 
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edwin_m

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MENTOR has certainly been around for a while and I think you're right regarding APT testing in the late 70s but I can't actually confirm this.

BR Research developed interial track geometry recording in the early 70s, fitted to the High Speed Track Recording Coach which I think is still around but will have had upgraded equipment several times by now. Laboratory Car 5 was the development vehicle for this technology, or rather three vehicles as it was originally a DMU and then an early Mk2 coach before finally becoming a Mk2 aircon (by which time it was known as the AEA Technology TrackLab I think). Note that Test Car 5 was something different. Much of this technology was sold to SNCF (for a measuring TGV) and RENFE (loco-hauled track recording coach with swappable bogies for different track gauges) and possibly elsewhere.

I was working on a contactless OLE geometry measurement system at BR Research in 1988 but I don't think it ever came to anything, and I'm not sure whose technology is used on the current fleet of measurement trains.
 

himarele

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The majority of OLE inspection is performed using monitoring equipment on survey trains, such as the New Measurement Train and a specialist vehicle known as MENTOR (an acronym for Mobile Electrical Network Testing, Observation and Recording, which is typically used these days to test new OLE installations).

Firstly, thank you again Philip. It looks like you know a lot of things about these equipments. I have been looking information about that and I have read something about MENTOR... a little strange.

I have discovered a report by Network Rail about an incident. They said that they was using MENTOR but it is said: 'The MENTOR coach, as configured prior to January 2013, did provide warnings to maintenance teams if its data suggested a possible alignment problem, but Network Rail standards did not permit maintenance teams to rely on this data.'

Why did they not rely on its data? Is it a new equipment? Has it been proven?
--- old post above --- --- new post below ---
I was working on a contactless OLE geometry measurement system at BR Research in 1988 but I don't think it ever came to anything, and I'm not sure whose technology is used on the current fleet of measurement trains.

Thak you Edwin! I am very interested in your opinion because of your experience. Do you know another contactless OLE geometry measurement system? Because I know some equipments developed by some Spanish companies really interesting but I am not sure...

How did you use that equipments? In static auscultations or in dynamic... What parameters did it control?

Sorry for my silly questions but I am a little lost in these themes... :oops:
 

edwin_m

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The system I was involved in just sat on the track as a static measurement but was intended eventually to go onto a rail vehicle to measure dynamically. It consisted of a beam resting on the track with a laser at one end directed onto a rotating mirror and a CCD (probably) sensor at the other end. By knowing the mirror position and the pixel of the sensor that picked up the reflection off the wire it is possible in theory to compute the height and stagger. Hence it was a more hi-tech equivalent of the traditional insulated measuring pole.

However the laser power was very limited because of the risk that it could shine into the eyes of the operator, and this meant that it was difficult to distinguish the reflection in bright daylight. More recent systems scan the laser much more rapidly and are mounted on the roof of the vehicle so there is less risk of it going into someone's eye and if it does it is only for a very short time, so I think they can use a more powerful laser and overcome the problem of insufficient brightness. Being much closer to the wire helps with this too, and also makes it easier to get accurate measurements.

However that was nearly 30 years ago and I haven't been involved with anything similar since then.
 

Philip Phlopp

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Firstly, thank you again Philip. It looks like you know a lot of things about these equipments. I have been looking information about that and I have read something about MENTOR... a little strange.

I have discovered a report by Network Rail about an incident. They said that they was using MENTOR but it is said: 'The MENTOR coach, as configured prior to January 2013, did provide warnings to maintenance teams if its data suggested a possible alignment problem, but Network Rail standards did not permit maintenance teams to rely on this data.'

Why did they not rely on its data? Is it a new equipment? Has it been proven?

Do you have a link to the report ?

I can't say for certain without knowing what the data was, but as with most Network Rail monitoring vehicles, MENTOR carries development equipment as well as production equipment, there's a constant emphasis on recording more data, improving the quality of data, measuring new parameters, cutting the cost of recording data and improving reliability of the equipment, so there's regularly a new or improved bit of technology on MENTOR.

It may be that the problem was picked up by a development sensor and there was no confirmation on the production equipment.

EDIT - it's my old friend, the Littleport RAIB report.

The OLE at this location was prone to rotational movement of the mast foundation, but with MENTOR, it had no definitive datum point for where the contact wire should have been when it visited the track. The vehicle, at the time, was also unable to take lateral movement of the coach into account, so every time it visited the track, it got different readings which sometimes under estimated the rotational movement of the catenary, and other times over estimated the movement of the catenary. The changes were wrongly attributed to lateral vehicle movement (the section of track is very exposed and high constant wind speed deflects the catenary and the vehicle itself, to different extents) and no definitive rotational movement could be determined.

This photo shows the actual problem (thanks again to whoever linked me to it). https://www.flickr.com/photos/justindperkins/23102379859/
 
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himarele

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Do you have a link to the report ?

https://www.gov.uk/government/uploa.../file/410743/130520_R062013_Littleport_V2.pdf

(Footpage of page 35)

Maybe, I didn't understand well, my English isn't very good and all these concepts are new for me... your explanations are very helpful for me. Thanks!!
--- old post above --- --- new post below ---
The system I was involved in just sat on the track as a static measurement but was intended eventually to go onto a rail vehicle to measure dynamically.

Very interesting! Normally the equipments only can do static measurement only dynamical, isn't it?
 

edwin_m

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Very interesting! Normally the equipments only can do static measurement only dynamical, isn't it?

By "static" I mean the equipment would have to be picked up and carried somewhere else, and there would be no pantograph present so it would measure the rest position of the OLE. You get different results if there is a pantograph present because that will lift the wire, and probably different again if the pantograph and the measuring equipment are moving.
 

Philip Phlopp

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By "static" I mean the equipment would have to be picked up and carried somewhere else, and there would be no pantograph present so it would measure the rest position of the OLE. You get different results if there is a pantograph present because that will lift the wire, and probably different again if the pantograph and the measuring equipment are moving.

An excellent series of points.

Just to add, for himarele

The majority of Network Rail's in-house measurements today are taken with pantograph down using the New Measurement Train, whilst the equipment on service trains (such as the new ThamesLink Class 700 trains) will be recording with the pantograph up.

That allows, if it's needed or wanted, a comparison between the OLE when it's used with and without a pantograph applying uplift force.

Static testing and low speed testing is generally restricted to installation testing, either new electrification, re-wiring, re-modelling of track and associated OLE or repairs after a dewirement. There may be some limited static testing if there's issues with pantograph carbons being chipped/damaged, and there's also bit of work ongoing with Furrer+Frey, Network Rail and various contractors to use drones for this sort of thing.

The combined approach - more data recording, new ways of recording data and the recording of additional parameters is solely to improve the reliability of the OLE systems used, we want to catch issues before they result in dewirements.

We can usually find the root cause of a dewirement, but much of the research work now is to find out what, if anything, we can see or detect before a dewirement, such a thermal signature from a damaged insulator, different/unusual oscillations which show a tensioner or pully has become sticky, before it seizes completely, or even bird feathers on the catenary to indicate a bird strike.
 
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