Ride in total comfort with Thermo King's World Class Climate Control Systems. Thermo King Bus and Rail HVAC Coach HRT-I LRT — Large Coach AC MRT — Medium Coach AC SRT— Small Coach AC Transit/City Citi RT Shuttle/School Bus ShuttleAire SR-15 ShuttleAire S-20 II ShuttleAire S-30 II ShuttleAire S-40 II ShuttleAire S-45R ShuttleAire SR-50C ShuttleAire SR-50S Light Rail LRV Heating Systems Driver Heater/Cooler Air Duct Heater Under Floor Heater Entrance Heater Convector Heater Technology Brushless Motors Controllers ClimaAIRE™ IntelligAIRE II™ Compressors X426 and X430 S391 Screw Compressor Refrigerants R-407C