OIL-FIRED heaters designed to preheat diesel locomotive engines and protect them from damage in cold weather have been adapted for use as low-maintenance water heaters on passenger coaches.

Manufacturer AST has modified the heaters so they can operate independently for periods of several weeks at extremely low temperatures. Air is taken in through a dedicated duct, ensuring that no oxygen is taken from inside the vehicle and that, in the event of a fault, no exhaust fumes can escape into passenger areas. Electrical preheating of the intake air allows the units to function reliably at temperatures as low as -30íC, and forced ventilation of the exhaust pipe gives optimal efficiency of combustion across a range of temperatures.

Four-way mixing valves completely separate boiler and heating circuits for the best distribution of energy on-board. GSM-R links allow staff to be alerted to any faults by text message, e-mail, or fax, and is it possible to start the preheater by sending an SMS message from a mobile telephone.

AST Energie & Umwelttechnik, Germany