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Railway safety

In 2021 there were 17 collisions, of which 16 at a level crossing. This involved 6 fatalities, of whom 5 at a level crossing. In response to a fatal rail accident at a level crossing near Hooghalen in 2020, NS and ProRail conducted an investigation. They published their joint conclusions and recommendations last year. NS has since begun adapting the colouring of the front of its SNG Sprinter trains, has formulated supplementary requirements regarding the collision resistance of the driver's cabin and is also examining escape routes for drivers. It remains NS’s ambition to close all uncontrolled level crossings; we will continue our dialogue on this issue with the Ministry of Infrastructure and Water Management, ProRail and others.

The investigation into the accident near Hooghalen in 2020 has revealed that in certain conditions, heavy or long vehicles do not have enough time to cross a non-actively protected level crossing (NABO). This is why 25 of these NABOs will be closed and another 4 will be protected.

Signals passed at danger (SPAD)  

In 2021, a total of 33 SPAD (signal passed at danger) incidents were registered. This is comparable to the number in 2020 (32) but much lower than in 2018, when 61 SPAD incidents were recorded. In 7 cases the train reached a danger point, such as a switch (2020: 5). NS's target is 0 danger point SPADs. Once again, this result can probably be attributed to a combination of measures, such as the stricter braking criterion (technical enforcement of more powerful braking when approaching a red signal) for VIRM and ICM trains, ORBIT (a system that warns drivers when they are approaching a red signal too fast) and TimTim/RTA (route information), and factors such as reduced pressure on the transport process as a result of an adapted timetable.

DDZ back in service 

On 3 December 2020, NS decommissioned all 49 DDZ trains for an indefinite period of time. This decision was based on a study in response to reports from employees on our trains on operational instability of DZZ rolling stock when run at higher speed. A technical investigation revealed that the braking system of DDZ trains causes wear and tear and deformation of the wheels. To prevent this from happening, we adapted both the braking system and maintenance practices and set up a monitoring system. The new braking system was extensively tested in the second half of 2021. Based on the insights gained from these tests, an integrated risk analysis of the measures to be implemented and regulatory compliance tests by external authorities, NS decided to redeploy the DDZ from the end of 2021 in phases.

Safety is an integral part of major changes

When implementing innovations, renovations and changes NS always maps out the risks involved for railway safety, and takes and monitors control measures. The main risks in terms of railway safety are collisions, fire, derailment and passengers falling under a train or being squeezed between a train and a platform. In the context of major changes, safety and the Human Factors (HF) discipline are integrated into the development process from an early stage, in terms of costs and lead times. NS incorporates HF in the design and development of innovations and in the design and implementation of HF-related policies. In addition, HF is applied in designing the interaction between people and technology within the framework of Automatic Train Operation (ATO) and in initiatives such as the Technically Controlled Departure Process (TGV). Another example is ERTMS, the programme that NS worked on in 2021. We assess the impact of these programmes on the safety of the transport system in order to make sure the safety level at least remains equal. In addition, HF has been taken into account in the requirements for new rolling stock and the assessment of user processes for ERTMS.


The ORBIT system warns train drivers when they are approaching a red signal at too high a speed. As such, the system can prevent signal passed at danger (SPAD) incidents. Since mid-2018, all Intercity trains have been equipped with ORBIT. In 2021, we finalised the installation of ORBIT in the last rolling stock series, Flirt and SNG. This means that all Intercity and Sprinter trains on the main rail network now have ORBIT. NS also conducted an exploratory study into the use of ORBIT data to detect weaknesses in the system and demonstrate its effectiveness. This has improved our insight into the circumstances that potentially result in SPADs. The data analysis has also revealed that both ORBIT and the stricter braking criterion have had a positive effect on railway safety.

Adapting the braking criterion  

Back in 2017, NS decided in principle to impose a stricter braking criterion for IC rolling stock. In 2021, we successfully converted our VIRM trains. The conversion of ICM trains is on schedule: we have completed the conversion of the ICM-3 and ICM-4, and will start conversion of the ICM-1 and ICM-2 in 2022. We have also started converting our DDZ trains. In addition, in 2020 we decided to also apply a stricter braking criterion for our Sprinter trains. We expect to initiate this in 2022, starting with SLT-type Sprinters.


In 2021, the Ministry of Infrastructure and Water Management, NS and ProRail discussed the issue of an added functionality in STM ATB, a solution that uses transponders between the rails to gather and transmit train data. This technical solution substantially improves rail safety at relatively low costs. The addition of this functionality is of huge importance to NS in its efforts to curb risks as much as possible. The Ministry is now assessing this in the relevant policy context with a view to adding the functionality concerned. Talks between NS, ProRail and the Ministry are ongoing.

Safety culture 

NS aspires to further develop its proactive safety culture and join forces to create a safe working environment. We do so by listening to each other, being open about safety levels and being aware of the risks involved in our work and our working environment. During the national Safety Week in October, we highlighted the importance of safety and a safety culture. We also conducted our third safety culture measurement in 2021. The results show that the safety culture is becoming more and more proactive. Both within separate teams and within NS as a whole, agreements are being made on targeted campaigns to further develop and strengthen our safety culture.

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