A light source 400 for use behind a lens arrangement 36, 38 of a signal aspect 18 of a railway light signal configured to use a filament lamp, wherein the light source is a LED light unit comprising: a LED driver circuit comprising an elongate LED element; and a mechanical support member 404 for supporting the LED driver circuit and the elongate LED element on a component 30, 32 of the signal aspect configured to receive a filament lamp, wherein the elongate LED element substantially replicates the location and orientation and incandescent profile of a filament in the filament lamp for which the signal aspect was configured and wherein the LED driver circuit comprises a dummy ballast load resistor 512 causing the LED light unit to consume substantially the same electric power as the filament lamp for which the signal aspect was configured. The LED light unit is designed to be directly substituted for a filament lamp.


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    Title :

    Railway light signals


    Contributors:

    Publication date :

    2015-11-18


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    English


    Classification :

    IPC:    H05B ELECTRIC HEATING , Elektrische Heizung / B61L Leiten des Eisenbahnverkehrs , GUIDING RAILWAY TRAFFIC



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    Engineering Index Backfile | 1910


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    British Library Online Contents | 2004