MEAN WELL is one of the world's largest manufacturers of switching power supplies and DC-DC converters, with production in Taiwan and China and a catalogue containing thousands of standard versions. The manufacturer's business model is based on catalogue products available from stock - without custom-designed projects, but with datasheets that precisely specify the scope of testing.

For rolling stock, MEAN WELL offers four families of DC-DC converters powered from the onboard battery and tested to railway standards: RSD (30–500 W, enclosed, EN 50155 class S1/TX, EN 45545-2), DDR (120–480 W, DIN-rail mounted, EN 50155, EN 45545-2), RQB (40–150 W, potted quarter-brick modules with 14–160 V DC input, EN 50155 class S2), and RSDW/RDDW modules (20–60 W, PCB- or DIN-rail mounted, EN 50155). The datasheets for all families include shock and vibration testing in accordance with IEC/EN 61373 and electromagnetic compatibility in accordance with EN 50121-3-2.

The input ranges of the available versions cover the standardized onboard battery voltages of 24, 48, 72, 96, and 110 V DC, including the tolerances required by EN 50155, while wide-input versions (14–160 V DC) support all of these batteries under a single part number. For circuits requiring EN 45545-2 fire protection compliance, the datasheets confirm conformity for the RSD and DDR families.