A system and process for operating a track trencher excavation machine includes multiple mode propulsion and steering controls that perform a plurality of functions depending on a selection of one of a plurality of operational modes. A computer modifies the functions of the multiple mode propulsion and steering controls depending on a selected operational mode, and coordinates propulsion of the engine and track drives of a track trencher in response to signals produced by the propulsion and steering controls. A display communicates status, fault, and other information to an operator during track trencher operation. Operator presence within a control area of the track trencher is monitored. Excavation and track trencher operation is interrupted upon detection of an operator leaving the control area. Automatic shutdown of the engine preferably occurs upon detection of one of a plurality of severe anomalous operating conditions.