Thanks, Brendan, for your advice and heads-up about the Rix wand.
I discovered that Rapido manufactures a product called the RailCrew Remote Uncoupler that appears to be worth taking a good look at [https://rapidotrains.com/produ...ch-machine-uncoupler]. Consisting of a 1-3/4” diameter by 7/8” long cylinder and toggle switch, it reportedly provides a reliable means to uncouple locomotives, passenger or freight cars equipped with any major brand of magnetic knuckle coupler. The cylinder sits between track rails under the roadbed and is active only when the switch is in the “on” position; an LED located on top of the cylinder simultaneously illuminates to mark the uncoupling zone. Couplers are unaffected when the switch is "off.” The uncoupler can be controlled by a DCC accessory decoder if desired.