Research conclusions ： Especially to the 10 kV distribution system of high - speed railway, an RAMS evaluation model which is based on the failure mode and effect analysis ( FMEA) is built. With a self - developed software, RAMS of all kinds of 10 kV distribution system in high - speed railway is evaluated. And through the contrastive analysis, some conclusions are found out as follows. If the external power supply is reliable, all kinds of power supply mode of double-continuous power line and single-continuous power line with contact line as reservation source have a availability ratio more than 99.99%. Double - continuous power line with power cable and load looped network switch is the best mode, which has an availability ratio 99. 997%. All the power supply modes of single-continuous power line have an availability ratio less than 99. 99%. Above all, the power supply mode of double-continuous power line is a key step to get better RAMS indices．