Yard hostlers (also known as yard tractors, terminal tractors, or utility tractor rigs) are common at port terminals, rail yards, and distribution centers.  Their function is to move containers around a facility.  At a port, containers are loaded off a ship onto a bobtail rig that is pulled by the yard hostler to an intermodal point or to a storage facility.  Yard hostlers are often idling as they wait in queues to pick up or drop off their loads.  

The ports of Long Beach and Los Angeles (POLB and POLA) contracted CALSTART to manage a project that demonstrated three (3) diesel-hybrid yard hostlers at the Long Beach Container Terminal (LBCT). This was a technology demonstration and evaluation program aimed at reducing emissions in (nonroad) marine terminal environments. As part of this project, vehicle emissions and performance were evaluated compared to baseline diesel yard hostlers. Following the testing and evaluation phase, a business case assessment was performed for expanding the use of hybrid yard hostlers in marine terminals and similar applications. The U.S. Environmental Protection Agency also provided funds for the development of the hybrid drive system.

The project was successfully completed. Read the final report at the POLB website.