MTH 20-21155-1 George H.W. Bush Train Sd70Ace Diesel Engine W/Protosound 3.0 (Hirail) Cab Number 4141. Beginning in 2019, M.T.H. will release 4141 and 9096 locomotives in four different iterations: RailKing O Gauge; Premier O Scale; HO Scale; and an all-new RailKing One Gauge model.