Architectural complexity management of engineering systems is becoming a major issue as systems built nowadays implement more complex technologies and innovations. In this paper, we present a preliminary research finding where quantitative values for an engineering system's architectural complexity are mapped with design effort for individual subsystems that are part of the system architecture. This was done to establish relationships between abstract architectural complexity of engineering systems and metrics that can directly be applied to system design and development. A railroad train driving bogie was used for the case study.