Riyadh Metro: An engineering marvel

The scale of the Riyadh Metro project was unprecedented on a global level, presenting new challenges for Ricardo's safety experts.

Situated in the centre of the Kingdom of Saudi Arabia, the recorded population of Riyadh, the capital, registered little more than 100,000 at the mid-point of the 20th century. 

Thirty years later - at the beginning of the eighties - its population had only just breached the million mark.

The opening of King Khalid International Airport in 1983, however, changed everything, spurring rapid urban expansion in every direction. Today, Riyadh is the largest city on the Arabian Peninsula and home to approximately 7.5m people.

But urbanisation also brought many of the challenges faced by all metropolitan centres across the world, not least transportation. Here was a major international city without any form of mass transit to alleviate the notorious traffic gridlocks that built every day on its main thoroughfares.

In 2013, the Royal Commission for Riyadh City (RCRC) awarded three separate Design and Construction (D&B) contracts to construct a six-line automated metro network that, once fully complete, would be the largest driverless urban transit system in the world. 

Ricardo was appointed by RCRC in 2015 to provide the Employer’s Independent Safety Assessment (E-ISA) services on the Riyadh Metro Project.

Bringing international insight and experience  

“Previous E-ISA roles on metro projects in the region meant we had built a strong understanding of the safety processes that support the planning, implementation and commissioning of new railways in the Middle East,” says Dan Wardle, Ricardo’s Project Director and General Manager of Ricardo Rail Limited – Saudi Arabia Branch.

“This meant we were able to bring the benefits of recent experience to Riyadh from the outset.”

“We worked diligently with all contractors to carry out a thorough programme of ISA activities, which ultimately helped to improve the quality and robustness of the technical safety demonstration that was produced in the contractor safety case documentation.”

Covering all six lines, Ricardo's E-ISA services centred around the assessment and auditing of the safety management and safety assurance activities for the three Design & Build Consortiums (BACS, FAST and ANM), with respect to their responsibilities for the design, build, manufacture, integration, testing, commissioning and handover of the railway engineering systems, both at individual subsystem and integrated system levels.

Our remit included safety plans, hazard logs, design safety cases, and verification, testing and acceptance plans. 

Furthermore, for the two appointed Operations and Maintenance contractors, CAMCO (who manage Lines 1 and 2) and FLOW (Lines 3-6), our teams were tasked with assessing operational and maintenance readiness (for both trial running and passenger service), as well as rule books, hazard logs and day-to-day operational processes and plans.

E-ISA assessment reports were produced for each Line at every major project lifecycle phase, helping the project to obtain the necessary approvals, and supporting the issue of Safety Certificates and Operating Licenses by the Transport General Authority (TGA) – the railway regulator for Saudi Arabia.  

Ambitious build programme brought unique challenges

Naturally, a project of such scale and ambition brought challenges, starting with the establishment of the safety process to be followed by the project.

“Due to the high number of stakeholders involved in the simultaneous construction of six new metro lines, it was important to foster a close relationship between all stakeholders, whilst still maintaining our independence,” says Dan.

“From the start, we arranged regular interface meetings involving all stakeholders as we sought to build connections and strengthen the overall level of safety assurance for RCRC.”

“During the early days of the project we produced the ‘approvals routemap’ to illustrate the path to acceptance and outline how specific stakeholder deliverables were all intended to come together in an efficient manner and enable the TGA to authorise the system into operation. This gave everyone involved in the approvals process clarity throughout each stage.”

“Another important early step was the work to define and specify a ‘Value for Preventing Fatality (VPF)’ that was appropriate for use in Saudi Arabia. This VPF was agreed with the TGA and adopted by the Design & Build Contractors in their safety risk assessments to help assure whether potential design options were justified or otherwise, in accordance with their risk assessment process.”

“Similarly, we helped the project stakeholders use a risk ranking matrix that was suitable for demonstrating the achievement of the ‘As Low As Reasonably Practicable’ (ALARP) risk reduction principle, and ensured that it was consistently applied across the whole project in accordance with CENELEC standards and railway guidance.”

Beyond the safety process considerations, there were also challenges of a technical nature.

“A particular area that required consideration was the at-grade barrier (safety measure) that physically segregates the metro from the adjacent highway traffic," explains Nasir Malik, the Ricardo Project Manager.

"We worked with D&B Consortiums to assure that the project had thoroughly risk assessed and justified this area of the design that protects the safety of the driverless system from road vehicles, in accordance with AASHTO specifications and associated guidance,” says Nasir.  

“We also had to evaluate risks related to the environment. For example, it is not unusual for temperatures to approach 50 degrees in the height of summer, so the potential for heatstroke or heat exhaustion of passengers during an evacuation (such as from a failed train between stations) had to be investigated. Again, working with the D&B Consortiums led to the specification of a maximum walking distance between egress points for both ground-level and elevated sections, which were not subject to standard requirements (as is the case for tunnel sections).”  

“Another focus was to challenge the Consortiums on areas of the design where we felt there was an overreliance on the Operator or Maintainer for manual intervention. On these points we would evaluate whether specific design features could be automated to provide a safer system response and minimise the potential for human error. For example, an automated intervention of the signalling system in response to an onboard derailment detection alarm, as opposed to a manual intervention by the operator, as mandated by standards.”

"Throughout the project we were able to positively influence the safety assurance of the overall system through our assessment activities," says Nasir.