Allash, Dmitry S. Varga, and Leonid G. Novakovsky FAROS-ALEPH Joint-Stock Company, Remik-2 Open Company, Moscow E-mail: pharos-alef@yandex.ru ABSTRACT The necessity to modernise traditional headlights used on operating underground rolling stock, and the technical feasibility of this task implementation are described. <...> Specifi c technological solutions developed by FAROS-ALEPH Joint-Stock Company and introduced to various series cars of the Moscow underground are presented. <...> Keywords: underground, underground car, headlight, light emitting diode, light distribution, luminous intensity, adjustment, optical camera, modernisation Since 2010 a range of lighting devices with light-emitting diode light sources for application in underground cars have been designed and ready for implementation, which meet all the somewhat inconsistent requirements of underground operation. <...> In work [1], the technological solutions of these devices were described in detail, a new approach to their standardisation was proposed, and values for the main lighting parameters were recommended. <...> However, by the time of the testing period of the 81–760 model car, its design and consequently the structure of most of its light devices (LD) were already confi rmed. <...> Headlights with light emitting diodes (LED) were the only objects of the operational tests as parts of the products, because the headlights would replace the traditional headlight units (Fig. 1). <...> The tests were performed in accordance with the standard technique; installation of the headlights on a car, adjustment of the light beam position with measurement of illuminance in a check point, and running in a real operating conditions for up to 30000 km. As a result of the tests it was found that: • The headlight’s lighting characteristics completely meet the standards for comfortable working conditions of an engineer in tunnels; • When coming to a station, the headlight illuminance level causes blinding of the passengers on the platform. <...> A conclusion arises: when the train is coming into a station, the driver should darken (dim) the LEDs in order to decrease the illuminance from the headFig. 1. <...> Headlamp units of the 81–760 model underground train: a) – traditional version; b) – pre-production model of the light-emitting diode headlight unit 46 Light & Engineering Vol. 23, No. 1 Fig. 2. <...> Appearance of the light-emitting diode headlamp unit lights <...>