This is a N Scale derailer for Code 55 Track The derailer is removable you just slide ot on and off the end of the rail. It is unidirectional and can be used with the sign on the inside or outside of the track. It is functional and will derail rolling stock.

For Code 55 print it at size L 5.84mm x W 9.65mm x H 2.5mm. Add .2mm to the width for Code 80 track.