National CSIRT.CZ team participated on Cyber Czech exercise on 23rd and 24th of May. The goal was to improve technical skills and even more importantly cooperation between team members and with lawyers and media. The topic of the exercise was defence of computer network simulating train traffic control against cyber attacks. Four of our team members trained alongside with teams from Hungary, Austria, Slovakia and Czech GovCERT.CZ. The exercise took place In Cybernetic Proving Ground of Institute of Computer Science which is part of Masaryk University. The first day was about getting to know the infrastructure and the second day was already filled with attacks, queries from news and management and fixing unavailable services for “regular users”.