The TCARS computer system was used aboard Wells-class timeships, such as the USS Relativity. On the Relativity, it could be used to locate past problems in a timeline along with performing normal starship computer routines. (VOY: "Relativity") The on-screen appearances of term "TCARS" is entirely in lower case letters, and wasn't spoken in dialogue. It appeared on the viewscreen diagrams, and in a series of dialogs depicting the temporal disruptor and the Kazon encounter.