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The Future of Hydrogen and Electric Transportation

During August 2019, Iarnród Éireann undertook trial stabilisation works to the track at Corracullin bog on the border between Co Offaly and Co Westmeath, with the objective being to trial a method of track stabilisation without removing the tracks, writes Colin Hedderly.

The benefit of a more stable track is a lower deterioration rate of track geometry meaning less corrective maintenance is required by mechanical tamping machines.

Of greater significance in the long term, however, is the potential to bring about an increase in permissible speed in areas where the weak underlying subgrade causes the track to deflect under load.

The deflection of the track under a passing train results in a Rayleigh Wave propagating in front of the train. A speed restriction is necessary to ensure the train speed is kept below the velocity of the propagating Rayleigh Wave which is known as the ‘critical velocity’.

If the train were to exceed this ‘critical velocity’ it would generate large amplitude track deflections and have implications for safety.

Background


Studies show that bog covers around 21% of the surface area of Ireland which is more than any other country in Europe except Finland (Tanneberger et al., 2017).

The rail routes constructed through Irelands central plain involved construction of many miles across bogs (O’Dwyer and Cox, 2015). With depths of peat varying in thickness up to 20m (70 feet), to excavate or embank on these unstable masses was obviously impossible (Jennings, 1994).

The method of railway construction across bogs is attributed to G.W. Hemans and is described in his Account of the construction of the Midland Great Western Railway of Ireland, over a tract of bogs, in the counties of Meath and Westmeath published in 1851. Thanks to this record we have a good understanding of how railways were constructed through bogs in the 1840s and 1850s.

Construction involved dewatering the top layers of the bogs by excavating a system of horizontal and lateral drains along the intended line of the railway.

Once the drainage was working well and the bog formation subsided, two courses of heather sods were then laid to a width of 30ft on the consolidated bog surface, which had previously been given a profile rising to 18 inches at the centre, much in the manner of crossfall on a road (Cox and Gould, 1998).

The rails were bolted directly on to longitudinal timbers, which in turn formed part of a 25ft wide lattice framework bearing on the prepared bog surface.

The result was that no part of the track could deflect suddenly without fracturing, and both sides supported and counterbalanced each other (Cox and Gould, 1998). In some locations the track needed to be lifted by nine to twelve inches every day to make good the settlement that had occurred overnight.

This continued for many weeks and eventually settled down but vibration and differential settlement has always affected the track in these bog areas (Jennings, 1994).

In more recent times, the practice has been to increase the weight of the formation without causing formation failure. Experience was the guide rather than theoretical analysis.

Initially a 600mm deep mixture of limestone, chips and dust was laid in 200mm layers and above this was laid the ballast and track (Jennings, 1994). The conditions have stabilised but continue to require a high level of maintenance tamping.

The author is aware of a number of instances where formation failure did occur from overloading. The most notable of these being in April 2001 near Ballymote, Co Sligo, where failure occurred during tamping operations of newly relayed and recently ballasted track.

The track here was situated on a 3m-high embankment constructed over a peat bog. The failed section was reconstructed using lightweight polystyrene blocks to reduce load on the peat foundation.

Track bed stabilisation without removing the track


The engineering principle of piles acting as a steady support for structures built on top is long established and Iarnród Éireann has used piles previously to stabilise railway embankments.

In 2009 at Tubber bog in Co Galway piles were used in combination with a designed geogrid reinforcement to stabilise and support the track. To implement the design at Tubber bog it was necessary to remove the track and the work took several weeks to complete.

However, the uniqueness of the trial at Corracullin bog in August 2019 is that the piles were installed without removing the track.

The methodology to do this has been developed to allow the installation be carried out at night during 'engineering hours' and with minimal disruption to the normal operation of trains during the daytime.

Figures 4 and 5 illustrate the stress distribution in a simulated loading model before and after piling.

Trial pile installation works


Piling specialist Van Elle carried out the works using their remote controlled VE-SPIRIT mast drilling system. This is a fully caged rotary system with automatic cut-offs to maximise safety.

The piles installed were Van Elle’s Smartpile system which is based on screwpile technology. Each pile uses helical flight sections top and bottom to transfer load to deeper more competent layers.

Piles were installed in pairs in every sleeper bed at the ends of the sleeper. They were installed based upon a designed length to reach the more competent layers and a minimum required torque measurement correlating to pile load capacity.

The pile cap is kept 800mm below the bottom of the sleeper to be clear of any future track maintenance and renewal works.

Ground investigation was carried out in advance of the works involving window sampling and dynamic probes at regular intervals throughout the site.

This confirmed the existence of a substantial deposit of peat underlying the entire trial site of between 2.1 and 4.2m in thickness.

A conservative thickness of 4.5m for this layer was adopted by the designers in the pile layout design.

The ground investigation also confirmed that the ballast and track construction depths throughout the site were considerable at 1.2 to 1.5m in thickness.

This build-up in ballast depth under the track has accumulated over many years from the repeated correction of differential settlement by maintenance tamping and topping up with ballast.

In the short-term each top-up and tamp increases the trackbed stiffness modulus, but in the long-term the additional loads from topping up the ballast only contribute to the inducement of further track settlement which compounds the issue.

Analysis of track maintenance records confirm the site has been tamped seven times in the past six years which is a high level of maintenance intervention.

Atkins were engaged as design engineers to prepare design calculations and analysis of the buckling resistance of the piles.

The approach taken was conservative omitting all skin friction around the pile shaft because of the weak nature of the peat material and relying predominantly on end bearing resistance.

From the installation records, based on a correlation determined by Van Elle using CAPWAP (Case Pile Wave Analysis Program) and installation torque values, the piles achieved a vertical capacity ranging from a minimum of 147.7 kN to maximum 295.4 kN, with an average of 224.6 kN.

Measurement of improvement


In order to provide an immediate measure of improvement from the works, void monitoring equipment was installed on the track for a month prior to, and a month after installation of the piles.

The equipment was called VoidMate and supplied by Garco Ltd. It provides a continuous recording of local deflections at track level under train loadings.

The VoidMate unit is clamped to the rail and operates by measuring the vertical displacement of a plunger placed directly upon or within the upper ballast layers. See image of VoidMate equipment in figure 8.

There were a total of six void monitors installed within the trial site. The results from the two void monitors located at the centre of the trial site area show a clear reduction in vertical track deflections following installation of the piles.

The average reduction in deflection in both cases is approximately 50%. Figure 9 is the summary results for one of these monitors (ref. 22029) which shows a reduction in average deflection from 5mm to 2mm. The reduction in maximum deflection is from 25mm to 2mm.

Summary


The trial achieved its objective by demonstrating a methodology of stabilising the ground through piling without having to remove the track and disrupt train services.

The results of the trial are very promising and clearly show an immediate significant reduction in deflection magnitude, whilst the installation method created little disturbance to the track.

Further assessment of the trial site using Falling Weight Deflectometer equipment is hoped for in the future. This is another method to assess the support stiffness to the sleepers.

A comparison of data from the test site with the adjacent non-piled track would provide another measure of the improvement.

In all 146 No. piles were installed in the trial with valuable experience gained in the logistics of undertaking this type of work.

There are areas where further efficiencies will be gained, but the installation time of 9 minutes for a pile to a depth of 7m was typically achieved during the works and was deemed efficient.

One potential concern following the trial was whether the change in trackbed stiffness would be sudden and noticeable from a passenger comfort point of view. This has not shown itself to be an issue of concern.

The way the vertical load distribution spreads out below the sleeper combined with the pile cap being kept 800mm below the bottom of the sleeper provides for a transitioned change, and this was proven by the VoidMate monitors situated at the beginning and end of the trial site recording a reduced improvement in deflection magnitude.

As to the future and the authorisation for more of this work it will come down to a favourable cost to benefit analysis and funding.

Individual sites will have to be assessed for their benefit and in particular the opportunity of higher speeds and journey time improvement that can be delivered by it.

There is further work to be done here but in principle it has been demonstrated that there now exists an engineered solution that can be targeted to stabilise areas of weak underlying subgrade without interfering with the running of trains.

A short video of the installation work can be found here:

[embed]https://youtu.be/nrB5EFd-ZAM[/embed]

Acknowledgements


The author acknowledges the support from all colleagues who worked on the project in Iarnród Éireann, and also to Van Elle and their John Allsop and Martin Gregory especially.

Author: Colin Hedderly is a senior track and structures engineer with Iarnród Éireann. He is a chartered engineer with more than 20 years’ experience in the rail industry in Ireland and the UK and is the lead engineer for the western division of the chief civil engineer's department, which has responsibility for maintenance and renewal of the track and structures.

References


1.) Aalen FHA, Whelan K, Stout M (1997) The Atlas of the Irish Rural Landscape. Published by Cork University Press.
2.) Cox RC, Gould MH (1998) Civil Engineering Heritage Ireland. Published by Institution of Civil Engineers.
3.) Hemans G (1851) Account of the construction of the Midland Great Western Railway of Ireland, over a tract of Bogs, in the Counties of Meath and Westmeath. Transactions of the Institution of Civil Engineers of Ireland, vol. 4.part 1. 1851. pp 48-60.
4.) Jennings PO (1994) I’ve been Workin’ on the Railway. The Institution of Engineers of Ireland Presidential Address.
5.) Musgrave P, Wehbi M, Jackson L, Stevenson A, O’Neil L, (2017) A Guide to Trackbed Micropiling. Published by Network Rail IP Track Bed Design & Innovation Group. See https://www.thepwi.org/technical_hub/technical_hub_files/a_guide_to_track_bed_micro_piling
6.) O’Dwyer D, Cox R, (2015) Early Irish Railway Construction. The proceedings of the Second Conference of the Construction History Society
7.) Powrie W, Le Pen L (2016) A Guide to Track Stiffness. Published by the Cross Industry Track Stiffness Working Group
8.) Tanneberger et al. (2017) The peatland map of Europe. Paper published by the International Mire Conservation Group and International Peatland Society.

Iarnród Éireann trial to stabilise tracks with underlying weak subgrade at Corracullin bog

Mechanical engineering students from Bolton Street teamed up with their peers at the College of Business, Aungier Street, to present a case study on a green transport system design for Galway.

They were representing TU Dublin at the recently held ESB Inter-Colleges Challenge at the Irish Management Institute.

Green metropolitan transport system


Samuel Berry, Pierce Blackmore, Jake Rogers and Sanchit Aggarwall presented their case study on 'Decarbonising the Transport infrastructure for Galway' and developed a winning proposal on a green metropolitan transport system for 2040.

Marguerite Sayers, ESB executive director, customer solutions and president of Engineers Ireland, presenting the team with the McLoughlin perpetual trophy.

Their win, competing with nine other Universities, meant they retained their crown having also won the competition in 2018.

ESB executive director and Engineers Ireland president Marguerite Sayers said: “The quality of analysis undertaken by each of the teams over the past two days demonstrates their ability to think critically and creatively about the challenges facing the country and the energy sector in the transition to a low carbon future.”

The TU Dublin team were mentored and coached by Dr Sajad Alimohammadi and Prof David Kennedy from the School of Mechanical and Design Engineering, and Dr Eoghan O’Grady from the College of Business.

According to Prof Kennedy, “the members performed to an excellent standard, demonstrating a very high ability in engineering, business and multidisciplinary team work combined with exceptional communication and presentation skills. This is the formula to excel in this competition”.

Dr Alimohammadi said "Ireland is committed to promote the UN’s Sustainable Development goals. Looking at the case considered for the competition by ESB as Green Transport System, it is perfectly aligned with and directly addresses three major goals as Affordable and Clean Energy, Sustainable Cities and Communities, and Climate Action”.

The team will now represent Ireland at the international engineering and commerce competition ENGCOMM in Montreal, Canada. Dr O’ Grady committed to ensuring the team will be fully prepared for this challenge and “will once again represent Ireland with great distinction at this very prestigious international competition”.

TU Dublin wins ESB Inter-Colleges Challenge 2019

Improving public transport can be a very difficult task - but what if cities could tap into big data’s unlimited potential to make better decisions?

Passenger mobility patterns


Thanks to SIADE SaaS, they can now discover passenger mobility patterns and uncover the strengths and weaknesses of current or planned urban transport networks.

The SIADE SaaS (Spatial Decision Support System for Transportation Planning) project essentially marks a change in the positioning of Spanish SME Terrain Technologies.

From a consultancy service built around an algorithm to infer passengers’ destinations, the company requested support from Horizon 2020 to become a software supplier.

Now, cities across Europe can benefit from a solution enriching big data with a spatial component, enabling complex analysis of travellers’ behaviour to improve public transport networks.

María J Arguelles, project co-ordinator, tells us more about the company’s solutions and accomplishments so far.

How can big data help provide a better public transport experience in Europe?
Smartcard ticketing systems currently available in many cities’ public transport systems enable a vast amount of data.

These datasets reflect how people behave, which in turn means it is possible to assess their transport needs and provide an accurate picture of their habits, either as groups (based on fare types, such as student, elderly and so on) or at an individual level.

Thanks to big data analytics, we can adapt public transport to these needs, plan new services, minimise walking time and so on.

What have been the shortcomings of attempts to use this data so far, and how does your software stand out in this regard?
It is important to clarify that big data brings great complexity to transport because of something inherent to it: what is commonly defined as the ‘5 Vs’ (volume, velocity, veracity, variety and value).

For example, a large amount of data volume implies large storage capacity. We can’t forget that cities like Madrid generate almost 500 million trips per year, and around 1.2 billion for the whole of the greater Madrid area which is almost as many as in Istanbul.

The variety dimension involves datasets generated from different sources such as bus validators or mobile phones, while veracity highlights the importance of quality data and the level of trust.

To complicate the picture even more, the fact that transport records are related to geographical locations means that we are dealing with data with a spatial component, or spatial big data.

To overcome those difficulties, SIADE SaaS has been designed as a core-GIS development, merging the spatial nature of data with advanced data analytics methodologies.

How exactly do you make up for the absence of information on passengers’ destinations?
That’s one of SIADE’s core algorithms. We can infer up to 88 per cent of passengers’ destinations with an accuracy of 96 per cent.

These results confirm that we are very strong in building origin destination matrices based on transport data, and are much faster, less expensive and more complete than those generated by using a traditional methodology in public transport: interviews.

It is important to note that our matrices are based on millions of records, while interviews are based on a small percentage of the whole population.

What have you been able to achieve thanks to EU funding so far? What do you still need to achieve before the end of the project?
The project was based on the understanding that we needed to change the business model and turn it into SaaS (software as a service).

But this is a costly process, so without EU funding we wouldn’t have achieved that goal so fast. The project also involves several transport consultancy companies, transport operators and/or transport agencies across Europe, which have been paramount in testing SIADE versions.

Besides that, we are lucky to be supported by a group of coaches provided by the EU that guide our decisions in the market strategy. We have already finished two of the three phases of the project, including the full analytics module and the simulator.

The simulator can predict with an accuracy of 93 per cent the changes in passengers’ flow after altering or deleting any of the elements in a transport network, such as bus stop, lines, transfer policy, frequencies, and so on.

We are currently in the big data phase, solving all the problems related to the 5 Vs. Parts of the algorithms have been successfully refined to adapt to the new framework.

Can you provide a few examples of challenges from specific clients that have been overcome thanks to your technology?
Sure. For example, we have successfully shown that bus transport in Oradea (Romania) wasn’t covering the whole city centre efficiently.

In Gijón (Spain), we found, thanks to the simulator, that changes in route 14 would increase the commercial speed, but at a price: people living in one of the neighbourhoods affected by the new route design would stop being bus customers, while most of them would use another route (18) instead of using transfers.

In Modena (Italy), the data model has been improved and changed to exploit SIADE’s capabilities much better. Our suggestions to create a circle route in Gijón have also been implemented in the city’s new mobility plan.

Can you tell us more about your market reach at this point?
We are currently collaborating with several transport consultancy companies to explore together tender opportunities in Spain, Latin America and Eastern Europe.

The fact that we have a successful project funded by the EU is an extraordinary competitive advantage.

What are your follow-up plans, once the project is completed?
We are succeeding in creating a platform that fits our customers’ and partners’ needs 100 per cent, so we expect to continue evolving in other markets outside of Europe and Latin America, such as the United States and Canada.

Big data enables better urban transport networks

Drive specialist maxon and Swiss car racer Sébastien Buemi team up to share their passion for precision, efficiency, and emobility.

Racer Sébastien Buemi knows what precision and efficiency are. After all, the former F1 driver has already won 13 races in the new Formula E and was the world champion in 2016.

Fully electric race series


Being fast is not enough to be a frontrunner in this fully electric race series, a driver must also be efficient with the available energy, or the battery will be empty before he reaches the finish line.

That's why Sébastien Buemi is a perfect match for maxon, whose high-end electric motors can be found not just in Mars rovers, but also in the Ad-Blue injection systems used in Formula 1 race cars.

maxon has decided to collaborate with Sébastien Buemi, and the parties signed the contract on September 9.

To celebrate the occasion, Buemi visited maxon in Obwalden to get to tour the company and meet the maxon team. Buemi was impressed with the cleanrooms and the tiny drives with a diameter of only four millimetres.

Swiss collaboration


When the Formula E starts into its sixth season on November 22, the Swiss collaboration will be represented by the maxon logo on Buemi's racing suit. Buemi will also act as an ambassador for maxon.

He says: “I'm proud of working with a Swiss high-tech company and being part of the maxon family.”

The joy is mutual. Eugen Elmiger says: “Sébastien and the Formula E in general are a great match for maxon. After all, we are increasingly becoming a systems provider, and the e-mobility market is particularly interesting in this regard.”

The Swiss specialist for quality drives


maxon is a developer and manufacturer of brushed and brushless DC motors. as well as gearheads, encoders, controllers, and entire mechatronic systems.

maxon drives are used wherever the requirements are particularly high: in NASA's Mars rovers, in surgical power tools, in humanoid robots, and in precision industrial applications, for example.

To maintain its leadership in this demanding market, the company invests a considerable share of its annual revenue in research and development.

Worldwide, maxon has more than 3,000 employees at nine production sites and is represented by sales companies in more than 30 countries.

Swiss racer Sébastien Buemi is now a member of the maxon family

Roadbridge Ltd is rolling out electric vehicles and smart chargers across many of its larger construction sites nationwide.

CarCharger EV Limited has provided www.EasyGo.ie networked chargers into the Roadbridge head office at Limerick and at multiple large construction sites around Ireland.

The installed smart EV chargers have the ability to instantly respond and use less power if the grid becomes overloaded.

Installed smart chargers into staff homes


To be-future-proofed, Roadbridge has also installed smart chargers into the homes of staff driving company electric vehicles which are wi-fi enabled to allow drivers to charge at off peak electricity rates overnight.

With Roadbridge drivers signed up to EasyGo.ie, they are able to access a country wide network of public chargers including those at Aldi, Centra, Lidl and SuperValu as well as those on the ESB network with single account access.

CarCharger is delighted that Roadbridge took the time to consider becoming future-proofed when installing EV charging infrastructure.

This is the latest step undertaken by Roadbridge as part of the #drivinggreenconstruction initiative.

Roadbridge go E-Car smart

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