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

Verster to leave ScotRail for East West Rail

20/01/2017Verster to leave ScotRail for East West Rail

Phil Verster will be leaving his current position as ScotRail’s managing director, which he has held since 2015, to become the MD of the Ea... more >
Khan accused of lying over failure to extend TfL fares freeze to travelcards

20/01/2017Khan accused of lying over failure to extend TfL fares freeze to travelcards

London mayor Sadiq Khan has been accused of reneging on his pre-election pledge of a TfL-wide fares freeze after it was revealed that it would ha... more >
‘Transformational change’ in Wales franchise hinges on new trains and electrification

20/01/2017‘Transformational change’ in Wales franchise hinges on new trains and electrification

A committee of MPs has urged the Welsh and UK governments to end underdevelopment of the Welsh rail network, pointing to the new Wales and Border... more >
A one-industry call for skills development

20/01/2017A one-industry call for skills development

At the launch of the new Rail Sector Skills Delivery Plan in December, key industry figures got together to outline how the major strategy will s... more >

editor's comment

17/01/2017Rising to the digital demand

The countdown is well and truly on for this year’s UK Rail Industry Awards (UKRIA), and the whole RTM team is looking forward to welcoming you to the fourth edition of this event on 9 February.  Held once again at Battersea Evolution, the prestigious awards ceremony promises to be an extraordinary evening, celebrating some of the major achievements of the industry in the last year. You can see the awards shortlist on pag... read more >

last word

Making rail fares simpler

Making rail fares simpler

David Sidebottom, passenger director at Transport Focus, explains how a number of initiatives over the next 12 months aim to make rail fares simpler. By the end of 2017, we hope passengers will see fairer and simpler fares.  Two recent... more > more last word articles >

interviews

Investing in the future of Scottish Rail

15/11/2016Investing in the future of Scottish Rail

Phil Verster, managing director of ScotRail Alliance, speaks to RTM’s Luana Salles about the recently-published ‘Investing in the Fut... more >

the sleeper's daily blog

Commuters close to taking government to court over Southern crisis

06/01/2017Commuters close to taking government to court over Southern crisis

A commuter organisation looking to take the DfT to court over its handling of the Southern rail crisis have said that their legal challenge is almost ready. The Association of British Commuters (ABC) hopes to submit its full application calling for a judicial review by the end of this month, after initially raising funds for the challenge... more >
read more blog posts from 'the sleeper' >

comment

Exhibitors prepare for France’s rail technology showcase

20/01/2017Exhibitors prepare for France’s rail technology showcase

Florence Gaidet from Mack Brooks gives RTM an update on what people can expect from SIFER 2017, France’s showcase for railway technology, p... more >
The data-driven railway

20/01/2017The data-driven railway

RTM speaks to James Dean, Network Rail’s director of route asset management (DRAM), LNW, about the work the infrastructure owner is carryin... more >
Achieving efficiency through standards

17/01/2017Achieving efficiency through standards

Vaibhav Puri, head of standards policy at the RSSB, attempts to bust the myths around standards, and argues that they will be vital to the tradin... more >
A digital railway for a modern Britain

17/01/2017A digital railway for a modern Britain

David Waboso CBE, managing director of Group Digital Railway, discusses using digital technology and how we must work together better as an indus... more >

rail industry focus

View all News