Roof-mounted modular air-conditioning system (HVAC) to supply 20kW cooling and 7kW of heating, to ensure a cabin temperature of 20°C-25°C max in a 45°C ambient, provided the coach is thermally insulated. The HVAC system is a double evaporator design with dual compressors (8kW and 12kW) for redundancy and capacity control. The system is available with reverse cycle heating, where the 8kW circuit is reversed to produce 9kW of heating.

The HVAC system does not restrict the standard operational features of any coach type and stays within the standard gauge set. The HVAC unit is protected with a sheet metal cover that matches the style and colour of the coach. For best results, two rooftop HVAC units must be installed per coach (one on each end). The rooftop HVAC system is qualified for shock and vibration according to BS EN 61373.

All electrical components and switchgear are housed in the control panel installed in the electrical control room of the coach, and no electrical parts are housed in the rooftop unit. This means that faults can be determined without needing access to the rooftop HVAC unit. All faults and trips can easily be addressed from the control box, without needing access to the rooftop HVAC unit.

All electrical connections, looms and the electronic control panel, as well as electrical control gear, are designed and selected for operation in railway environments, which include adverse temperatures as well as severe shock and vibration.

The HVAC unit is equipped with custom-designed electronic controllers, capable of all control and safety functions. The touch screen controller activates subsystems as required to regulate the cabin temperature to the desired setting on the control panel (HMI). The system has a Bluetooth login interface for remote monitoring via a smartphone app and/or laptop. Installation of the unit requires substantial modifications, and it is suggested that the system is designed with the correct interfaces in place.