Inbox

24.07.15

Detecting track defects

Source: P.C Johnson

In the 1970/80’s various test trains were developed as individual facilities to assess various track features and brought into service as separate operations. Four of these major units were the Ultrasonic Test Unit, Track Recording Unit, the Structure Gauging Train and Lab 5, a track Recording Coach already in long term use. Even at that time there were thoughts of eventually combining these operations into a possible single unit to reduce line occupancy, costs and some of the duplicated staffing aspects. In a combined arrangement the speed of testing would be determined by the test requiring the lowest testing operational speed requirement and possible light level requirements.

The track recording facilities could work at any speed up to line speed with a constraint of a comparatively slow minimum low speed. The installation of track recording facilities as a unit on conventional ‘in traffic’ stock gives some aspects of the track being travelled over but does not give specific detailed information and tends to be influenced by the riding characteristics of the vehicle conditions on which it is installed. The Structure Gauging facility worked at similar but preferably slightly lower speeds principally at night. The Ultrasonic facility had the lowest speed requirement determined by the time taken for the transmitted shear wave ultrasonic energy to return from the bottom of the rail and the pulse spacing to ensure full coverage. This restricts the speed of operation to around 20 to 30mph.

My recollection of detected in track rail defects and failures indicated in general they were usually located in the upper half of the rail. Rail-end defects in the lower web were usually associated with other defects in the upper half of the rail. The few other true rail foot defects usually occurred in known galling and corrosion areas and could be accommodated accordingly.

Testing down to mid-rail depth would allow a significant increase in testing speed. However this approach would not be without difficulties, needing to ensure residual energy from consecutive events did not interfere. With an increase of speed it would be necessary to maintain the density of pulsing to ensure full examination coverage. However with the current computing facilities available and a designed multiple probe arrangement it should be possible to produce a system to overcome these problems.

Work to enhance the fracture toughness of rail steels would also improve defect resistance to failure. A more extensive use of the more expensive, but probably cost effective, rolled High Manganese steel rails, in vulnerable areas, with their tolerance of significant cracks without failure. Although this material does carry penalty of a lower propagation speed of ultrasonic energy adding to difficulties in automated processes.

Filming of track and pantograph features could also be incorporated with its own constraints. In consequence I would suggest it should be possible, with careful planning, to carry out several measurement features on the same train/unit simultaneously reducing costs and track occupancy.

Re: Current IM fleet data collection service 'unsustainable'

Comments

There are no comments. Why not be the first?

Add your comment

 

rail technology magazine tv

more videos >

latest rail news

Transport for the North joint submission to the Integrated Rail Plan

03/06/2020Transport for the North joint submission to the Integrated Rail Plan

In a collaborative submission to the Integrated Rail Plan, Transport for the North’s Members have called for a sustained investment in the ... more >
Overnight work to overhead power lines at Euston

03/06/2020Overnight work to overhead power lines at Euston

Network Rail are advising passengers that there will be no services in or out of London Euston after 9pm this Thursday (June 4th) while work to o... more >
Tube stations begin phased return

03/06/2020Tube stations begin phased return

When lockdown began in March, many Underground stations were closed with only key stations remaining open.  On the May 18th, TfL annouc... more >
Network Rail reminds walkers in Whitby to stay off railway

02/06/2020Network Rail reminds walkers in Whitby to stay off railway

NR is warning people in Sleights about the dangers of trespassing on the railway following a series of incidents where walkers are using the rail... more >

editor's comment

23/01/2018Out with the old...

Despite a few disappointing policy announcements, especially for the electrification aficionados amongst us, 2017 was, like Darren Caplan writes on page 20, a year generally marked by positive news for the rail industry. We polished off the iconic Ordsall Chord (p32), hit some solid milestones on Thameslink (p40), progressed on ambitious rolling stock orders (p16), and finally started moving forward on HS2 (p14) ‒ paving the way for a New Ye... read more >

last word

Encouraging youngsters to be safe on the railway

Encouraging youngsters to be safe on the railway

This summer, Arriva Group's CrossCountry and the Scout Association joined to launch a new partnership to promote rail safety among young people. Chris Leech MBE, business community manager at the TOC, gives RTM an update on the innovative scheme... more > more last word articles >

interviews

Andrew Haines, CE of Network Rail, tells BBC News his organisation could issue future rail franchises

24/06/2019Andrew Haines, CE of Network Rail, tells BBC News his organisation could issue future rail franchises

Andrew Haines, the Chief Executive of Network Rail, has told the Today programme on Radio 4's BBC’s flagship news programme that he wo... more >

the sleeper's daily blog

Maximising efficiency requires investment in data, but it’s rewards for rail could be extensive

14/11/2019Maximising efficiency requires investment in data, but it’s rewards for rail could be extensive

Rail Technology Magazine’s Matt Roberts explains the significant role data can play within the future development of the rail industry. Standing as a cornerstone of the UK transport network, the rail industry is forever striving to innovate and maximise efficiency in all aspects of its work. Data is just one such way of achievi... more >
read more blog posts from 'the sleeper' >

comment

The challenge of completing Crossrail

05/07/2019The challenge of completing Crossrail

With a new plan now in place to deliver Crossrail, Hedley Ayres, National Audit Office manager, major projects and programmes, takes a look at ho... more >
Preparing the industry to deliver trains for the future

04/07/2019Preparing the industry to deliver trains for the future

The move to decarbonise the rail network involves shifting to cleaner modes of traction by 2050. David Clarke, technical director at the Railway ... more >
Sunshine future beckons for South Wales Railways, says 10:10 Climate Action’s Leo Murray

02/07/2019Sunshine future beckons for South Wales Railways, says 10:10 Climate Action’s Leo Murray

Smart electrification is the way to boost clean energy resources, argues Leo Murray, director at 10:10 Climate Action. Contractors are clear... more >
Ambition doesn’t have to be expensive, says Midland Connect's Maria Machancoses

02/07/2019Ambition doesn’t have to be expensive, says Midland Connect's Maria Machancoses

The TCR Midlands conference is only days away and tickets are going fast for the sector event of the year at the Vox Conference Centre in Birming... more >

rail industry focus

View all News