In case you were waiting for the MTH Christmas Engine, Rail King product #30-20436-1 it is now due to arrive January 2018 because they have had problems with packing and shipping the engine without causing damage to the LED Christmas type lights located around the engine itself. Sounds like poor planning for those wanting this product before December 25!
Dash-8 Diesel Engine With Proto-Sound 3.0 And LED Lights - Christmas (6-Wheel Trucks)