Material savings, flexible production and high user comfort are increasingly gaining importance in the field of railway vehicles. Analyses and simulations of passenger flows in vehicle interiors allow for an improved vehicle body layout. Mass-reduced manufacturing of sidewalls with individualized door-cuts can be optimized by low-distortion laser welding and completely connected integral structures. At the trade fair InnoTrans 2016 the Dresden Fraunhofer institutes IWS and IVI are presenting jointly developed technical implementations for passenger flow simulations and manufacturing techniques for low heat input and highly efficient laser welding procedures.