I know they do this for C track and I believe also for M track but I cannot find one to go with K track uncouplers. My main purpose is to be able to see in amongst the sidings with wagons on the track where the uncoupler is in relation to the train on the line. It maybe doesn't have to light up and could be just a simple light mast or mast. I am not overly prototype detail mad but a suggestion for something that would be Ok (or that you use yourself) would be much appreciated.