According to various aspects, exemplary embodiments are disclosed herein of assemblies that may be used for mounting enclosures of portable remote control locomotive (RCL) systems and/or speakers to locomotive handrailing. Also disclosed are exemplary embodiments of portable remote RCL systems mountable to locomotive handrailing by such assemblies. Additionally, exemplary embodiments are disclosed of audible alert systems including speakers mountable to locomotive handrailing by such assemblies.