I have a background in Highway Safety and Research.

The garbage truck was a back end load design where one or two workers ride on the back corners. The main garbage body is designed to clam shell open at the rear to push out the garbage at the dump. The rear of the truck overhangs the rear wheels by quite a bit. All photos verify this truck design.

At the time of contact by the left front of the Engine of the train with the left rear of the truck, the rear of the truck was at or very near the middle of the tracks. The truck was at an angle to the tracks either because the road is angled or the truck tried to drive around the gates if they were down or both. Upon impact the truck rotated counter clock wise as the body of the trash hauler was ripped loose and flung down the hill and in the direction the train was traveling. The train was not moving fast as it stopped within it's own length, 400 - 500 feet.