In 2017, when Hyundai Rotem was awarded a contract to supply 50 new electrical multiple units (EMU) for Seoul’s Metropolitan Line 4, the manufacturer chose to appoint Ricardo as Independent Safety Assessor (ISA) for the project. 

This was the first time a South Korean rolling stock manufacturer had sought conformity against international safety standards for an entire vehicle platform, rather than undertaking such assessments at a generic application level for safety-critical subsystems, such as onboard signalling, brakes or passenger door systems.

As the ISA, it was our duty to monitor the vehicle's design and manufacture stages, and ensure that recognised industry, legal and regulatory safety standards were being met.



Also known as the Blue Line, Line 4 is a complex route that extends more than 70 miles from Seoul's north-eastern districts through to its south-western commuter areas. As a result, the line is managed jointly by Seoul Metro, which oversees the 30 mile section through the city centre, and by national operator, KORAIL, in the suburban sections to the south and west - the sections known locally as the Ansan and Gwaechn lines.

This meant our assessors had to work closely with both KORAIL and Seoul Metro to ensure the new fleet would integrate seamlessly with the procedures and rules of both operators.