These are the Stud and Tag Washers for Turnout Motor Operation from Peco. The PL-18 Studs are inserted into the control panel, often laid out as a layout diagram. A wire is then soldered to the tag at the back, which goes to the relevant solenoid of the turnout motor. When power is applied by touching the powered PL-17 probe on the stud, the Turnout Motor is activated.