saw their first redesign since 1978. The ER and WestCoastER were given a much larger windshield, redesigned driver's compartment, and saw the introduction of several new diesel engines. To better compete with the Blue Bird TC/2000 and Ward Senator (which became the AmTran Genesis), Thomas replaced the Saf-T-Liner EF with the All Star, using an Oshkosh-produced chassis. The Thomas Vista continued production, shifting chassis in 1991 from General Motors to a variant of Navistar chassis shared with the Saf-T-Liner Conventional. In 1992, the fourth generation of the Thomas family took over daily operations of the company (becoming the first family-owned school bus company to do so). During the mid-1990s, the company began development of environmentally cleaner buses, with compressed natural gas (CNG) school buses entering production in 1993; several battery-electric school buses were produced in 1994 as prototype vehicles. By 1996, Thomas had become the largest school bus manufacturer in the United States (by market share). To keep up with added demand, the company opened a third factory in Monterrey, Mexico. As a design change, the "T-bus" roof emblem (used since the early 1980s) was replaced by a scripted Thomas Built Buses emblem (its predecessor). During the later 1990s, Thomas Built Buses would undergo a number of significant changes, with some that have changed the future of school bus manufacturing. For the 1997 model year, Freightliner introduced the Freightliner FS-65 school bus chassis. Derived from the Freightliner FL60/FL70 medium-duty trucks introduced in 1995, the FS-65 chassis was paired with the Saf-T-Liner Conventional body, after several modifications (distinguished by the addition of a 4-piece windshield). Transit expansion During the 1990s, Thomas modernized and expanded its product range within the transit segment. Alongside the Chartour and CL960/Citiliner, Thomas marketed Transit Liners, commercial derivatives of the Saf-T-Liner school buses, along with commercial versions of the Minotour and Vista. A dedicated transit bus derived from the Saf-T-Liner ER, the TL960 was a two-door bus that offered an integrated wheelchair ramp as an option. In 1999, Thomas entered a joint venture with British bus manufacturer Dennis to import the Dennis Dart SLF (in CKD form). Following assembly by Thomas in North Carolina; while badged as Thomas vehicles (the Thomas Dennis SLF200), distribution of the low-floor buses was undertaken by Orion Bus (itself becoming a Daimler subsidiary in 2000). Company acquisition Into the late 1990s, Thomas Built Buses remained a family-owned company, controlled by the fourth