Photo: Obninsk Research and Production Enterprise Technologiya named after A.G. Romashin
How to turn common glass into impact-resistant and also electrically heated glass for railway train cabs? The answer to this question is known to the personnel of Rostec’s group of companies in chemical industry whose parent company is Obninsk Research and Production Enterprise Technologiya named after A.G. Romashin. Having got through numerous processing stages, glass acquires the desired properties and is ready for installation on subway, commuter and long-distance trains.
How is the train cab glazing produced?
Cab glass is a multilayer structure installed in a rubber seal or metal frame. Electrically heated glass is equipped with non-contact temperature control. The key properties of glazing include high strength, light transmission of at least 70%, anti-ice and anti-fog system, and minimized optical distortions. The glass making process is described in more detail below.
The process starts from feed stock preparation. Glass sheets are fed to a work bench using a crane where they are cut to size. The bench is perforated to ensure air supply, thus, creating an air cushion on which the glass moves easily facilitating the cutting process.
Two glasses are generally used for the finished product: outer load-carrying glass and inner electrically-heated glass. After machining, the glasses undergo different manufacturing phases depending on their function.
A design is transferred to the outer glass using screen printing. This is made to protect the sealant, that is used to attach the glass to the cab, against ultraviolet light and to perform a decorative function concealing the current-carrying elements on the inner glass.
The inner glass becomes capable of getting warm due to a special current-carrying film. All glasses are tempered, for which they are first heated to 650 °C and then blown with cold air. This makes the glass impact resistant and safe. According to the standard, train cab glazing shall withstand a shot with a stone or bottle at a doubled train speed.
After tempering, metal strips are applied to the inner glass to carry current and will be used to solder wires to them. Then the outer screen-printed glass is added to the electrically-heated glass interlaid with polymer film. All this is accomplished in a dedicated clean room to avoid ingress of dust between the glasses.
The resulting three-layer ‘pie’, or triplex, is placed into an autoclave – kind of an industrial ‘multicooker’. The glasses are bonded in a whole there at a temperature up to 145 °C and a pressure up to 13 kgf/cm².
‘Technologiya’ for railroads
ORPE Technologiya manufacturers more than 400 glass products for railway transport, thus, having about 70% of the Russian market. Glazing to existing and future railway trains is developed and produced in Obninsk.
Glazing made by the Obninsk-based factory is used for 55 types of electric locomotives, 48 types of diesel locomotives, 14 types of electric trains, 3 types of railbuses and 26 types of track machines.
Photo: Press Service of the Moscow Government
Technologiya replaced foreign cab side glazing for the Lastochka high-speed electric train at the end of the previous year. Rostec’s products can be also seen in the Moskva-2020 and Baltiets subway trains. It was reported in June this year that Technologiya would provide glazing for new Minsk subway trains.
