Heating, ventilation, and air-conditioning in SBB rail vehicleses
CAN Newsletter Rail 2006
By Dr. Ralf Hofer (SBB Passenger Traffic Operations) and Michael Studer (Selectron)
The series Re 420/620 locomotives taken into service at SBB (Swiss Federal Railways) during 1967 to 1985 are fitted with a static base load heating system as standard. During the summer months, compartment air temperatures in excess of 45 °C are by no means rare. In view of this background, it is sensible to consider retrofitting the driver’s cabs with air-conditioning systems. SBB Cargo Industriewerk based in Bellinzona (Switzerland) was put in charge of overseeing the locomotives’ conversion.
In order for the air-conditioning systems to be operated, it was necessary not only to provide the power supply bus also the automation system as well as a range of peripheral items such as cabling, windows and air ducts in the vehicles. In addition, installation technicalities had to be taken into account and adaptations made to the locomotive body, i.e. making cut-outs in the locomotive side walls, fitting static reinforcements as well as integrating service doors and openings.
Air-conditioning system
Two air-conditioning systems are used in each locomotive. The key components of the air-conditioning system are compact air-conditioning units manufactured by Termogamma SA of Biasca. The air-conditioning units were designed to be used not only with energy-saving mixed-air mode but also in a mode referred to as “free-cooling” in which a high proportion of outside air can be used for cooling.
