Congratulations Dr. Nadjla Ghaemi for successfully defending your PhD dissertation on “Short-turning Trains during Full Blockage in Railway Disruption Management” today!
Nadjla’s PhD work has been published in the following journal publications:
Ghaemi N., Cats O. and Goverde R.M.P. (2018). Macroscopic multiple-station short-turning model in case of complete railway blockages. Transportation Research Part C, 89, 113-132.
Ghaemi N., Cats O. and Goverde R.M.P. (2017). A Microscopic Model for Optimal Train Short-Turnings during Complete Blockages. Transportation Research Part B, 105, 423-437.
Ghaemi N., Zilko A., Yan F., Cats O., Kurowicka D. and Goverde R.M.P. (2018). Impact of Railway Disruption Predictions and Rescheduling on Passenger Delays. Journal of Rail Transport Planning & Management. Accepted.
Ghaemi N., Cats O. and Goverde R.M.P. (2017). Railway Disruption Management Challenges and Possible Solution Directions. Public Transport, 9 (1-2), 343-364.
The defense was followed by a TRAIL seminar where I gave a talk on “Robust passenger transport systems: Network, operations and user adaptations”
How do disruptions propagate in public transport networks? for how long and how far away from the source are passengers affected?
In a new paper on Physica A: Statistical Mechanics and its Applications, we propose a method for quantifying the extent to which the network exhibits spillover effect.
Model results are evaluated for the Stockholm network using a dynamic non-equilibrium assignment model.
[News headline: Bomb threat against train travel; Travel chaos following two false bomb alarms; photo from Stockholm Central station]
Will be attending MT-ITS 2017, the 5th IEEE International Conference on Models and Technologies for Intelligent Transportation Systems, together with colleagues with whom I collaborated on public transport -related studies.
I am involved in the following contributions that will be presented in the upcoming conference:
- Analysis of Network-wide Transit Passenger Flows based on Principal Component Analysis. (Presenter: Ding Luo)
- Simulating the Effects of Real-time Crowding Information in Public Transport Networks (Presenter: Arek Drabicki)
- Impact of Relocation Strategies for a Fleet of Shared Automated Vehicles on Service Efficiency, Effectiveness and Externalities (Presenter: Konstanze Winter)
- Real-time Short-turning in High Frequency Bus Services based on Passenger Cost (Presenter: David Leffler)
- Measuring Spill-over Effects of Disruptions in Public Transport Networks (I will present work performed with Sanmay Shelat)
Looking forward to my first MT-ITS experience!
Added on 16-8-2017: links to all conference papers are available on the Publications page.
In the last several years, I have investigated the impact of service disruptions in public transport networks. In a series of network topology and dynamic transit assignment studies, I have looked into indicators of link criticality, measures of impacts on system performance, mitigation value of real-time information provision, identifying strategic links for increased capacity and the robustness value of new links and extension plans.
One common limitation to all of these studies was the lack of information on the probabilities associated with disruptions. This prevented a complete risk analysis and assessing the (e.g. annual) costs and benefits associated with disruptions and mitigation measures.
Together with Menno Yap and Niels van Oort, the frequency and duration of various disruption types on each public transport mode (train, metro, tram and bus) were estimated based on a unique dataset. We also identify which is the primary predictor of each variable to allow researchers and professionals in other contexts to estimate disruption probabilities in the lack of local data.
We propose a method for embedding link exposure into the identification and evaluation of critical links and perform a risk analysis for the multi-modal public transport network of the Rotterdam The Hague Metropolitan Area. By comparing the results with the conventional measures, we demonstrate that disregarding exposure risks prioritizing heavily utilized links instead of those which are actually the weakest.
Click here for the link to the full paper.
Investments in transport are increasingly motivated by the need to improve its robustness — the capacity to absorb disturbances with a minimal impact on system performance. Nonetheless, there is lack of knowledge on how to assess and quantify the robustness value of new investments as part of strategic planning. This study investigates the robustness of alternative public transport networks by assessing the consequences of link failures on network performance. A full-scan disruption impact analysis is performed and its implications on passenger’s group composition and travel time losses are analysed for a public transport development plan in Stockholm, Sweden. A decision to extend this system substantially with 23 new stations and 35 km of new tracks by 2025 was recently undertaken.
The results suggest that as a result of the development plan, the robustness of the case study network will improve in terms of average performance deterioration as well as worst case scenario for all performance indicators. Neglecting abnormal operations in project appraisal can potentially lead to the underestimation of its benefits. Moreover, the critical links in each network are identified and impact disparity is investigated. The analysis method presented in this study can support the consideration of development plan impacts on network robustness in the strategic planning process.
See here the full paper