Heating, Ventilation and Air Conditioning (HVAC) refers to the mechanical systems used to maintain suitable environmental conditions within railway buildings and infrastructure.

In railway stations, HVAC systems provide ventilation, cooling and, where required, heating for passenger areas, staff rooms, equipment rooms and other enclosed spaces. Maintaining appropriate temperature and humidity is particularly important in technical rooms containing signalling, telecommunications, electrical and control equipment.

In underground railways, HVAC interfaces closely with Tunnel Ventilation Systems (TVS). Ventilation systems must address both normal operating conditions and emergency scenarios. During normal operation, they help manage heat generated by trains, passengers, equipment and other sources. During emergencies, dedicated ventilation and smoke-control systems may be used to support passenger evacuation and emergency response.

Railway HVAC installations can include air-handling units, chillers, cooling systems, fans, ductwork, dampers, filters, pumps, sensors and associated control equipment.

HVAC equipment is commonly monitored and controlled through a Building Management System (BMS), PLC-based controls or SCADA interfaces.

Railway HVAC design must consider passenger comfort, equipment heat loads, outside environmental conditions, fire and life safety, smoke management, redundancy, maintainability, energy efficiency and interfaces with architectural, structural and railway systems.

mainline, high_speed, metro, light_rail, freight, station

ASHRAE standards and guidance; NFPA 130 where applicable; applicable local mechanical, ventilation, fire and life-safety codes; railway project specifications