Do you need to control it from a Lionel/MTH/DCC command control system? If not, or if you don't have command control, you can DIY a remote control (wireless) on/off to "any" rolling stock item by cobbling together eBay wireless remote control relay modules. $10-15 total out-of-pocket. The ERR "hotbox" appears to be $44.95 plus shipping.
If you're a DIY enthusiast you could even attach the transmitter fob to a Lionel ASC or MTH AIU so as to use your existing command-control remote.