ETCS Hybrid Level 3: simulation based assessment for the Dutch railway network

ERTMS

The combination of the Dutch mainline legacy signalling system NS’54 and Dutch automatic train protection system ATB-EG is functioning well but has some drawbacks. Both systems are old and components have to be replaced in the near future. The speed supervision functionality of ATB-EG is limited to only five speed steps and full brake supervision is lacking. ERTMS is proposed to be the new standard European railway safety system.
It could provide interoperability, enhanced safety and/or improved capacity over the existing national signalling systems.
The Dutch government decided back in 2014 to replace the legacy system by ERTMS/ETCS Level 2 on several mainlines by the year 2030. To fully benefit from all opportunities of Level 2, corridors have to be divided into short block sections, requiring a substantial amount of trackside train detection. This amount of trackside train detection would have an impact on reliability and is a costly asset, both in installation and in maintenance.The concept of ERTMS/ETCS Level 3 allows for even more capacity while eliminating trackside train detection. A high demand is put on both train and remaining trackside equipment. All trains need to be proven complete and the trackside needs to know the position of all trains all times to ensure safe railway operations.
To overcome those issues, ERTMS/ETCS Hybrid Level 3 comes into play: to combine the ERTMS/ETCS train position information i.e. the Level 3 principles with limited trackside train detection.Virtual subsections divide the physical detection blocks into smaller block sections. Position reports from the proven complete trains are used to authorise following trains at short headways, limited to the minimum of the size of the virtual blocks and the braking distance of a specific train. Following a train not being equipped with a Train Integrity Monitoring System (TIMS), safe operations is provided with the remaining trackside train detection.The capacity effect of ERTMS/ETCS Hybrid Level 3 is a trade-off between the amount of remaining trackside train detection and the amount of trains equipped with integrity monitoring. The reduction in asset costs is a trade-off between the capacity goal of a corridor and the amount of TIMS-equipped trains.This paper presents a simulation-based impact assessment of ERTMS/ETCS Hybrid Level 3 for the Dutch railway network for several corridors with varying numbers of TIMS-equipped trains and reduced trackside train detection. Although several theoretical studies and real-life tests have been performed over the last few years, quantification of the possible effects is lacking.
Using the Timetable Compression Method for the assessment of capacity effects and the RAMS-LCM approach for the assessment of asset costs reduction, this paper provides insight into the benefits of the implementation of ERTMS/ETCS Hybrid Level 3 instead of ERTMS/ETCS Level 2 for the Dutch railway network.