The report investigates consequences of modified track spacing on pressure waves induced by meeting high-speed trains. The aim is to investigate consequences in terms of an increased risk of fatigue of car body components and which potential counter-effects may have.The study is intended as a first investigation that should be valid under fairly generic conditions. Simplified analyses are employed due to the generic conditions considered. Under more specified conditions, refined analyses can be employed to improve the analysis and improve quantification of the various mitigating actions