With increased share of Static Frequency Converters (SFCs) in 16 2/3 Hz railway grids concerns about stability have increased. Stability studies for such low-frequency railway grids are few, and models that describe SFC dynamics are especially few. This paper presents an open SFC model for electromechanical stability studies in the phasor domain, suited for 16 2/3 Hz synchronous railway grids. The developed and proposed SFC model is implemented in MatLab Simulink, together with grid and loads. Numerical studies are made, in which the proposed SFC model is validated against both measured RMS-phasor amplitude of voltage and current at the railway grid side of an SFC. The SFC model developed is able to reproduce the measured RMS voltage and current with an acceptable accuracy.