Table 1.
Classification of unplanned tram stoppages in selected Polish cities
| City | Classification Basis | Number of Main Categories |
|---|---|---|
| Warsaw | Incident types; categories are treated equally without assigning responsibility | 16 |
| Kraków | Based on responsibility: third-party fault, city infrastructure fault, or operator fault | 3 (with subtypes) |
| Poznań | Responsibility-based with detailed subcategories under three main groups: vehicle-related, driver-related, and external causes | 3 (with multiple subtypes) |
Table 2.
Classification of unplanned tram stoppages in Poznań
| Related to the Vehicle | Related to the Operator | External Causes |
|---|---|---|
| Technical fault in the pantograph contact strip | Accident involving pedestrians/cyclists/other road users | Accident involving foreign vehicles in the track or its gauge |
| Pantograph actuator malfunction; pantograph structural damage (breakage) | Accident involving passengers | Blocking the track gauge by a badly parked vehicle |
| Converter malfunction – no charging of the tram battery | Vehicle accident with injured | Power outage – no voltage in the DC network |
| Derailment | Negative sobriety test of the operator on the route | Overhead contact system damage |
| Collision with another vehicle | Fainting of the driver, feeling unwell | Flooding of tracks after heavy rainfall |
| Vehicle controller and master controller (drive controller) failure | Vehicle halted on a section insulator – battery-powered departure not possible. / Failure of the sectional power converter – no possibility to leave from the battery | Frozen water in rails or switches – no possibility of passage |
| Failure – axle seizure | Vehicle entering a closed section of track – track work Power outage in the overhead contact system due to planned tram network outages - the driver’s lack of knowledge about planned tram network shutdowns | Other obstacles lying on the tracks: sand, stones, tree branches, shed, advertisement, etc |
| Damage to hinges/cardan wheels threatening derailment | Damage to track rails caused by their wear, threatening derailment | |
| Broken rail brake | Unplanned stop of another tram within the junction | |
| Unplanned stop of the preceding tram | ||
| Disruptions in tram traffic related to unplanned difficulties in the city: marches, events, emergency services, fire brigade, building supervision, etc. |
Figure 1.
Causes of unplanned tram stoppages in Wrocław in 2019
Source: own elaboration based on data provided by the Road and City Maintenance Authority in Wrocław.
Figure 2.
Monthly distribution of unplanned tram stoppages in Wrocław in 2019
Source: own elaboration based on data provided by the Road and City Maintenance Authority in Wrocław
Figure 3.
Weekly distribution of unplanned tram stoppages in Wrocław in 2019
Source: own elaboration based on data provided by the Road and City Maintenance Authority in Wrocław
Table 3.
Comparison of the condition of tracks in 2018–2020 (Wilczyńska et al. 2024)
| State | 2018 | 2020 | 2020 (aggregation) | Difference |
|---|---|---|---|---|
| Very good | 58% | 5.43% | 11% | −47% |
| Good | - | 5.92% | - | - |
| Average | 31% | 54.68% | 55% | +24% |
| Bad | 11% | 33.97% | 34% | +23% |
Figure 4.
Track condition in Wrocław in 2020
Source: own elaboration
Figure 5.
Tram derailments in Wrocław in 2019
Source: own elaboration
Figure 6.
Proportion of unplanned stoppages related to track condition in 2019 in Wrocław, categorized by track condition classification
Source: own elaboration