The SBB rail network has several thousand sets of points, plus around 36 000 signals along with their lamps. Control of these points and signals is occasionally lost. A fault may also occur in one of the approximately 500 signal boxes that control railway operations.

In these cases, we speak of a «technical fault in the railway system».

If the fault cannot be rectified remotely, a specialist travels to the site to look for the cause. Once the cause has been determined, SBB solves the problem on site. For simple faults, this can be done within minutes.

Where possible, SBB tries to bypass the disruption, for example by using the side track. If this is not possible, alternatives are considered, such as driving the train at reduced speed. Technical faults in the railway system can result in delays, track changes and train cancellations.

SBB trains travel through Switzerland and Europe from early in the morning until late at night. They cover thousands of kilometres a day through different climatic conditions and accommodate large numbers of passengers boarding and alighting. All of this generates a heavy load for vehicles. So, it is no wonder that things break down from time to time. If the disruption is caused by a train or a train door, it is referred to as a «vehicle fault» or a «door fault».

If a vehicle or vehicle component breaks down despite all preventive efforts, the train crew tries to rectify the fault on site by performing a mechanical operation or resetting the locomotive computer. Safety is always the top priority. In case of doubt, a train is not allowed to continue.

Did you know? Just like cars, trains also visit the workshop on a regular basis. Every seven to twelve days, vehicles make a four-to-eight-hour pit stop at a service facility.

Engine drivers and passenger attendants try to rectify the fault on site as quickly as possible with support from telephone help desk staff. If the fault cannot be rectified, the train is cancelled. If this happens, SBB announces alternative travel options and endeavours to replace the defective vehicle as quickly as possible – ideally from the nearest major railway station. Replacement trains for defective vehicles are stabled at six locations in Switzerland.

SBB passenger trains run exclusively on electricity and not on diesel, for example, as in other countries. The trains draw their power from a contact line (catenary) mounted above the tracks by means of a current collector. If the contact line is damaged and trains can no longer run on the affected section, this is referred to as a contact line problem.

Contact lines carry extremely high currents. Unlike in private households, where the voltage at the power socket is 230 volts, the current in the contact line is 15 000 volts. Even approaching the contact line can cause severe injury, which is why technicians must exercise the utmost caution in the event of a contact line fault. Before trained specialists arrive on site, the presence of dangerous «residual amounts» of electricity cannot be ruled out. To protect customers and staff, this means that there is a delay at the beginning of the disruption before the fault rectification process can get underway.

If there is a fault in the contact line, SBB is obliged to disconnect a small part of the network, which means that trains must be diverted or cancelled on the affected section. This often results in longer journey times. Although rail replacement buses are requested from bus companies within minutes, the companies need time to provide enough vehicles and staff. Particularly in the first few hours, waiting times and insufficient seating capacity are unavoidable.

Many trains operated by our foreign partner railways DB, ÖBB, Trenitalia and SNCF run as «domestic» trains from the Swiss border to their destinations, for example to the Bernese Oberland, Zurich or Chur. The trains are therefore integrated into the Swiss clock-face schedule. If these trains are delayed or cancelled due to an event or strike abroad, SBB communicates this accordingly, stating the country in question.

SBB does everything it can to minimise the impact of events in neighbouring countries on domestic passengers by organising punctual replacement trains or taking other measures to ensure that passengers’ journeys run smoothly.

When a replacement train is in use, SBB indicates this on the platform or in the online timetable, along with any changes to the formation of the train. For you as a customer, this may mean that the replacement train has no restaurant car or fewer seats, for example. But at least a punctual travel option can be offered and the train does not have to be cancelled.

If a defective set of points or a damaged track cannot be repaired quickly, a section of the line may need to be closed completely for a few hours while the repair work is carried out. In this way, the track can be repaired quickly and safely. SBB refers to work that is not planned in advance as «unscheduled construction work».

Whenever possible, SBB tries to schedule necessary repairs during low-traffic periods, such as at night. Nevertheless, it is unavoidable that you as a customer will face restrictions in rail traffic.

Unscheduled construction work may result in longer journey times or may mean that you have to transfer to a rail replacement bus. Depending on the situation, it may take SBB some time to get rail replacement buses and staff ready for service.

People or animals in the vicinity of the tracks, a collision with an animal, an obstacle on the tracks, a police operation or an accident involving a person: such incidents, which are not SBB's fault, have a negative impact on rail traffic. In these cases, SBB informs customers of the reason for the disruption.

Depending on the severity of the incident and to ensure the safety of people, animals and railway infrastructure, traffic may be stopped altogether or allowed to proceed only at a greatly reduced speed. If necessary, SBB emergency services and rescue services are deployed on site.

Depending on the scale of the incident, there may be lengthy restrictions on rail traffic, resulting in delays, diversions or train cancellations. SBB announces alternative travel options or organises rail replacement buses. Depending on the situation, it may take SBB a little time to get rail replacement buses and staff ready for service.

If you are on a train, pay attention to the information provided on board. SBB provides regular updates on the next steps and alternative travel options. At the same time, we recommend looking at the SBB Mobile app. By activating the «travel companion» function, you can also access the latest information here. We recommend re-entering your journey details. SBB Mobile displays suitable alternatives based on the operational situation, for example if additional stops are planned on the route.

If you are in a station, check the information at the station as well as the SBB Mobile app. SBB also provides information on the next steps via announcements and signs.

If services on the line are completely suspended and you have not yet started your journey, SBB will recommend alternative routes that are well away from the disruption (for example, passengers travelling from Zurich main station to Lausanne will travel via Biel/Bienne if there is an interruption in Bern).

If you have an important appointment like an exam or a flight, report to the staff or call the SBB Contact Center at 0848 44 66 88 (CHF 0.08/min.).

In the event of train cancellations, delays or line interruptions, you can take the next possible train without purchasing a new ticket provided you obtain confirmation from ticket inspection or sales staff.