Price is for 1 slave board this board can’t work independentlyit must work with a master board ( sell separately ) Click Here To View The full Instructions Functions:what can this slave board do?use it with a master board ( sell separately ), they may stop and restart the train before the rail spur.use it with a master board ( sell separately ), they may stop and restart trains at the station; or use them as shuttle train controller. PRODUCT DESCRIPTION how they work:the master board detects trains by bouncing invisible Infra-Red (IR) light off the underside of the rolling stock, or install it on track side, detecting the l...