Lego ALCO Type 4-8-8-4 Steam Locomotive

LDD recreation of an ALCO type 4-8-8-4 Union Pacific Big Boy. I tried to make this as detailed as possible yet, still 100% playable. It uses a PF motor in located in the firebox to drive all 16 driver wheels through an open differential in the boiler. The differential is needed to allow the driver trucks to pivot freely to allow the power to negotiate the tight Lego curved tracks. You can also disengage the motor from the rest of the drive by lifting and rotating the middle dome 180 degrees. The battery box is located in the tender. I went for realism so its wider than the standard Lego trains.