Thomas Saf-T-Liner C2

Coinciding with the development of the Freightliner Business Class M2 medium-duty truck, Freightliner began work on an all-new bus chassis to replace the FS-65 bus chassis. As the parent company of Thomas Built Buses, Freightliner sought to pair the new chassis with a new body design for its Saf-T-Liner Conventional (which had not undergone a complete redesign since 1962). The Saf-T-Liner FS-65 remained in production through the end of 2006, outliving the rest of the medium-duty FL-Series by nearly three years. To assemble the new model line, Thomas constructed a state-of-the-art production facility in its hometown of High Point, North Carolina, adding 275,000 square feet of production capability. In November 2004, Thomas delivered its first Saf-T-Liner C2 to Durham School Services; this bus was a 2005 model. In October 2012, Thomas delivered its 50,000th Saf-T-Liner C2 to Dean Transportation of Lansing, Michigan. In 2016, Thomas Built Buses released the 100th Anniversary model of the C2. In June 2018, the 100,000th Thomas Saf-T-Liner C2 was delivered to Montgomery County Public Schools in Virginia. ==Overview==

Design and manufacture As the Thomas Saf-T-Liner C2 marked the first completely new bus body for the company since 1962, Thomas redesigned a number of its manufacturing techniques coinciding with its introduction. To minimize the number of rivets and welds (a weak point of structural integrity on a bus body), adhesive bonding was used to complete a number of body joints. In the cases where fasteners are needed, self-piercing rivets are used. These engineered fasteners join layers of metal together without punching completely through the bottom layer, thus reducing the likelihood that rivets will become the source of leaks in the future. Chassis ISB6.7 in a Saf-T-Liner C2 As with all conventional-style school buses, the C2 is derived from a cowled-chassis conventional; the C2 uses the Freightliner C2 variant of the M2. As with 2000s and 2010s industry practice in school bus manufacturing, chassis and body manufacturers are paired, with Freightliner and Thomas developing the C2 as an integrated vehicle (the Freightliner grille badges are replaced with Thomas badges). At its launch, Mercedes-Benz MBE diesel engines were the standard engines, with optional Caterpillar C7 and Cummins ISB diesels. In 2008, the Cummins ISB6.7 replaced the MBE900 as the standard engine, with the C7 discontinued. From 2010 to 2018, the sole diesel engine in the Thomas C2 was the Cummins ISB6.7; for 2018 production, the Detroit Diesel DD5 becomes an option. The C2 comes standard with an Allison 2500 automatic transmission with an Allison 3000 automatic transmission as an option. The Saf-T-Liner C2 is the only school bus in North America offered with a manual transmission; a rarely ordered option is a Fuller 6-speed transmission. Body In a break from traditional bus body design, as body manufacturers acted as second stage manufacturers adapting the body to the chassis, in the design of the C2, Freightliner-owned Thomas Built Buses designed the body and chassis of Saf-T-Liner C2 as fully integrated components. A separate body from the Saf-T-Liner EFX/HDX and Minotour, the C2 body shares no parts with its Saf-T-Liner Conventional/FS-65 predecessor. While Freightliner has also produced cutaway-cab buses derived from the M2 for commercial/transit use, Thomas Built Buses is the only manufacturer to produce a cowled-chassis bus body derived from the M2. Coinciding with the shift to the Freightliner M2 cowl, several changes were made to improve the functionality over its predecessor. Most visibly, to improve aerodynamics, the traditional multipane vertical windshield was replaced by a sloped single-piece curved piece of glass (allowing the use of the stock windshield wipers). While initially equipped with an air-operated entry door, in 2012, an electric-operated entry door became offered as an option. Since 2016, a manually operated passenger entry door was added as an option. At the end of 2023, Thomas debuted the Saf-T-Liner C2 Evolved for 2025 production, marking the first major update to the C2 in over 15 years. While the underlying body structure saw few changes, the C2 Evolved followed suit with the updates of the Freightliner M2 Plus. Along with a digital dashboard and a stalk-operated transmission shifter, the update saw a modernization of the electrical system (allowing for better integration of future technology). Externally, the C2 Evolved adopted the slatted grille style of the M2 Plus (in line with the larger Freightliner Cascadia). ==Variants==

Alternative fuel powertrains In May 2014, Thomas Built Buses began production of a propane-fueled version of the Saf-T-Liner C2. Powered by a 339 hp 8.0L V8, the C2 Propane is paired with the Allison 2300PTS automatic transmission. The engine is designed by Powertrain Integration (an OEM supplier to General Motors) with the 8.0L V8 named the PIthon. In 2019, the propane engine was enlarged to a DriveForce-branded 8.8 L, supplied by Power Solutions International, which had acquired Powertrain Integration in 2015. In 2016, a compressed natural gas (CNG) variant of the Saf-T-Liner C2 was released. The first Type C (conventional-style) school bus produced with a CNG fuel system, the Saf-T-Liner C2 CNG is powered by a version of the Cummins ISB 6.7 engine. C2e (hybrid-electric bus) In 2007, Thomas introduced a hybrid-electric version of the Saf-T-Liner, named the C2e (stylized as C2e). The parallel hybrid drivetrain was designed by Eaton Corporation; the C2e retains the Cummins ISB engine and adds a 1.9 kW-hr lithium-ion battery pack with a 44 kW electric motor/generator. Annual fuel savings were estimated to range from assuming per year. This is a 20% increase in fuel economy, and the buses can drive under battery propulsion for up to . At least 24 C2e buses were built and delivered to operators in Kentucky and Michigan. In the summer of 2013, Thomas removed the C2e product literature from their website, marking its discontinuation. C2 Jouley (electric bus) In November 2018, Thomas unveiled a battery-powered prototype of the Thomas Saf-T-Liner C2 designated eC2 or "Jouley" (after the unit of energy). The prototype previews an all-electric C2 intended for production during 2019; it was developed in partnership with Proterra, Inc., who offer a line of transit buses using the same battery-electric drivetrain. The C2 Jouley uses a single traction motor with an output of (peak/continuous) and a two-speed gearbox; this configuration is branded ProDrive by Proterra. The traction battery has a total capacity of 220 kW-hr, providing a range of up to , assuming an efficiency of 1.4 kW-hr/mile ( equivalent). The bus is charged using the SAE J1772 CCS Combo 1 connector; a full charge takes approximately 3 hours using a 60 kW DC charger. The first large order for 50 Jouley buses was placed by Dominion Energy in December 2019 as the first phase of their school bus replacement program, to be delivered by the end of 2020. In February 2021, the Montgomery County Public Schools (Maryland), largest school district in the state, announced they had ordered 326 Jouley buses. On October 17, 2022, Thomas delivered the 200th Saf-T-Liner C2 Jouley to Indiana-based Monroe County Public Schools. Other uses Alongside its yellow school bus configuration, Thomas Built Buses produces multiple configurations of the Saf-T-Liner C2, including MFSAB versions (activity/childcare versions), along with the Transit Liner C2 commercial-use bus. Through aftermarket manufacturers, the C2 also serves as a donor vehicle for multiple types of specialty vehicles derived from bus bodies. ==Comparable products==

• Blue Bird Vision • IC Bus CE Series ==See also==