Pandrol AutoSeal creating a heat proof seal without the need for luting paste

As a standard-setting rail technology company, Pandrol is constantly driving industry innovations – leading the way for everything from environmental responsibility to technical best practice across the board

Now, as part of its enduring commitment to sustainability, Pandrol is taking steps towards improving its world-leading welding process. Having realised that the process itself had undergone minimal change since initial implementation, Pandrol spent time analysing its efficiency in terms of time, safety, accuracy and environmental impact. Armed with these insights, the organisation was equipped to create Pandrol Advanced, a brand-new process for better, more effective welding.

Pandrol Advanced harnesses innovation at every step of the welding process to save time and improve safety, ergonomics and weld quality. Aluminothermic welding traditionally involves luting – sealing moulds to rail ends with paste or sand to avoid metal leaks. But with Pandrol Advanced, the luting process is replaced by AutoSeal, the world’s first self-sealing mould. AutoSeal comes
with a built-in insulation joint that expands during pre-heating to create a tight seal when fitted onto the rail.

AutoSeal offers a number of key benefits that serve to make the entire welding process more efficient. Firstly, it reduces the time spent on each weld by a minimum of five minutes, thanks to its ability to automatically seal the mould and eliminate the need for luting. This moulding system also makes sealing more reliable, lowers the defect rate by evacuating moisture during preheat, and puts welders’ health first by reducing the time they need to spend kneeling.

AutoSeal also means less plastic waste, lower energy requirements and a reduction in overall environmental impact – making it a highly efficient alternative to traditional methods of welding.

The Pandrol Advanced process selects the smaller, CJ1 one-shot crucible rather than the larger CJ2 version, making it suitable for all standard gap and head wash repair welds, which accounted for 98.5 per cent of all welds cast by Pandrol in the UK in 2019. Thanks to pre-installation conducted by a Startwel electronic ignition system, the CJ1 design makes igniting the portion within the
crucible safer and easier. Using it as part of the Pandrol Advanced process also reduces waste, cost and requirements for packaging and transportation due to its lighter weight and non-explosive classification.

Fully optimised for use with Pandrol’s High Flow Preheater (HFP) – the universal preheating system brought in to replace all currently equipment – the Advanced process raises the parent steel’s temperature prior to welding. As opposed to the mix of oxygen and propane used by most existing preheating systems, the HFP uses pure propane, eliminating the cost of oxygen and improving the welders’ onsite experience thanks to the equipment’s lower weight and smaller canister. And with the ignition, timing and stop all fully automated, there’s no need for lengthy manual interference or flame adjustment.

As Frédéric Delcroix, Pandrol’s Welding Technical Director, explains: “Our High Flow Preheater’s built-in timer increases accuracy – improving quality and reducing the defect rate of welds due to preheating, which can be a real problem for rail operators. By providing a uniform preheat between the head and bottom of the rail, the High Flow Preheater reduces stress in the weld.

‘We’ve also made it easier to operate; there’s no need to adjust the torch height, which saves time, and as the system is fully automated, less training is required. It is straightforward for new welders to learn to operate, and offers the added reassurance that comes from knowing the preheat has been even.’

With the Pandrol Connect welding app giving welders the ability to manage the entire Advanced process digitally from their device, the method is more effective and environmentally efficient than ever. This technology means that instead of recording data manually, welders can input information straight into the app before, during and after welding, with reviewing carried out by welding controllers and monitored from the office.

The Pandrol Advanced process is paving the way for innovations across the board in contrition and maintenance. With more fit-for-purpose practices such as AutoSeal mould, the HFP and CJ1 crucible used throughout, the process has redefined what’s possible when it comes to environmental responsibility and efficiency in the welding process.

High Flow Preheater makes its début in Mongolia
Project case study

  • Tavantolgoi–Gashuun Sukhaitrailway, Mongolia
  • Customer – Bodi Group/INCON
  • Sector – Heavy Haul
  • Track length – 240 kilometres

The Tavantolgoi–Gashuunsukhait railway – approximately 240 kilometres long, with two stations and five passing loops – is set to be enormously significant for Mongolia’s economy. This new railway will allow Mongolia to increase its export capacity by 30-million tons of coking and thermal coal annually. As a result, the country’s mining companies will be able to compete in the global market for cheaper exports, supporting both coal exports and China’s ports.

The Pandrol battery-powered High Flow Preheater (HFP ) in use

Customer challenge
To complete the Tavantolgoi– Gashuunsukhait railway project, Bodi Group (one of the largest business groups in Mongolia) and its subcontractor InCon were looking for a great value welding solution that was versatile and reliable.

They turned to Pandrol for the solution and awarded the contract in early 2020, just before the onset of the pandemic. Pandrol’s aluminothermic welding product was used for hard-to-reach places such as switches and crossings, stressing points and any remedial works.

Under normal circumstances, a member of Pandrol’s specialist welding team would have travelled to Mongolia to carry out inperson training. However, border closures and travel restrictions made this impossible.

Pandrol solution
From July until September 2020, Pandrol supplied the aluminothermic welding kits and conducted the online training. With the High Flow Preheater (HFP) not ready for use at this time, Pandrol employed a traditional oxy propane preheating method, training the teams in Mongolia to use it correctly. This was a challenging phase of the project due to the equipment’s sensitive nature and the team’s lack of experience in this area.

Fish plates are usually used to secure tracks in Mongolia and the team on-site hadn’t seen pre-heating or used welding techniques before. With Covid-19 preventing in-person training, Pandrol
delivered bespoke, virtual training to seven railway workers in Mongolia. Supported by a translator, the trainees spent three weeks learning how to weld and how to use the equipment, both in a training environment and in situ on track. Teaching how to use the oxy propane preheating equipment virtually proved particularly difficult – its large flame can be disconcerting for new welders, and its high temperature can induce nerves at first.

Following training, each employee shipped a test weld to Pandrol’s headquarters in France for quality checks and certification. All welds passed the European inspection criteria however, some of the welds were showing signs of overheating due to the use and set up of the oxy propane equipment. Pandrol presented the results to the team in Mongolia, identifying that the preheating process in place needed improvement, and discussed the best solution.

By now, Pandrol was launching the Electric 230V HFP (High Flow Preheater) – a universal preheating system that raises the temperature of the parent steel before welding. Fully automated for easier, more reliable operation, the ignition, timing and stop are automatic and require no manual interference or flame adjustment. Using propane rather than oxygen and propane mixed reduces costs and makes the equipment light and portable.

The team in Mongolia were impressed with the product, recognising that it would put welders’ instantly at ease and remove safety risks. Almost a year after the contract signed, in March 2021, the HFPs were manufactured, shipped and delivered. The Pandrol team conducted HFP training, which resulted in an instant improvement in the welding quality. This was a fast, easy solution that empowered the Mongolian team to do the best possible job.

Adding value
‘We use new HFP equipment all the time and it greatly simplifies our work. Thank you for providing this new technology.’ Chinzorig Tumendemberel– Bodi Group

The results
Welding has continued successfully and rapid progress is being made on the Tavantolgoi–Gashuunsukhait railway. In 2021, more than 1,300 pieces of joint were welded on the main track. This year, the team is planning to weld 700 joints on the turnouts.

As Chris McKeown, Head of Operations for Aluminothermic Welding & Equipment for Pandrol UK notes, this has been a successful project on multiple levels. ‘It just goes to show that when we’re faced with challenges, we can be agile – bringing innovative ways of working to the table to the benefit of client outcomes.