There is described a control peripheral post of railway field devices, comprising: —at least one row of control modules operatively connected or connectable by electric cables to field devices; —a support frame having a front side and housing said row of control modules; wherein said support frame comprises at least one anti-extraction bar positioned on the front side of the support frame, said bar being adapted to selectively take an extraction configuration, wherein said bar is positioned in such a way as to permit the extraction of the control modules from the front side of the support frame, and a blocking configuration, wherein said bar is positioned in front of said row of control modules so as to prevent the extraction of the control modules (4, 5) of said row from the front side of the support frame.