We would like to express our sincerest condolences on the death of Professor Leo G. Kroon, who left us all too early in the midst of setting up the CASPT special issue. Leo was a Professor of Quantitative Logistics at the Rotterdam School of Management (RSM), Erasmus University, the Netherlands, and a Logistics Consultant at Netherlands Railways (NS). Leo was foremost interested in public transport and railways; this was from both sides, practical impact and academic rigor. He pioneered in developing a group of practical researchers and students at NS, who worked with “rolled-up sleeves” to solve real-world problems. Leo had a leading role in many international collaborations; for instance, he was the project leader for RSM for several EU-funded projects in railways.

Leo Kroon was among the founding senior editors of our journal and he was always up towards supporting in different roles, let it be as editor, referee, and author. Leo was not only member of the International Scientific Committee of the CASPT conferences. In 2015, he organized the conference in Rotterdam with a team of his students, colleagues, and his dearly beloved wife, Cisca. He and his team put every effort in organizing both the scientific and the social parts of the conference, where only the best of the best was acceptable for him.

After years passing there will be much to stay. This includes papers, memories, and especially the 2008 INFORMS Franz Edelman Award presented to NS where Leo was an essential part of the winning team. On behalf of the editors of Public Transport I would like to stress: we shall remember Leo for his work, for his support, and—most importantly—as a person.

Stefan Voß