High Quality Content by WIKIPEDIA articles! The Thomas Saf-T-Liner is the name of the transit-style (Type D) school bus product line produced by Thomas Built Buses. Introduced in 1978, the Saf-T-Liner marked the transition to in-house chassis production by Thomas. In addition to school bus applications, variations of the Saf-T-Liner have been produced as activity buses, specialty vehicles, and commercial/transit buses.