Havent looked in a catalog recently?
MTH has used a wireless drawbar between the engine and the tender for the past few years (when they were making steamers). Those models also have a hinged deckplate which spans the gap.
Lionel steamers of recent also have a wireless drawbar.
Lionel predates MTH in the use of a wireless tether by MANY years. The Lionel Lionmaster Challengers(Black UP #3983, Item #6-28077) were using wireless tethers at least as far back as 2001.
Doug