Two employees were moving a trailer mounted compressor by hand after disconnecting it from a truck. The two employees were pulling the trailer forward, moving closer to the back end of the original tow vehicle. As the momentum behind the trailer increased, employee 1 attempted to control the trailer by placing his hand on the trailer tongue. Employee 1's finger became caught between the towing truck's bumper and the edge of the trailer tongue. The employee' s little finger was amputated.