The MEAN WELL DDR-120 series DC to DC converters have been designed to comply with standards EN50155 and EN45545-2, so they are suitable for use on locomotives and passenger trains or trams. They are only 32mm wide and have a wide 2:1 input voltage range. There are four input options:
 
9~18 VDC
16.8~33.6 VDC
33.6~67.2 VDC
67.2 ~ 154VDC
 
The output voltage can be adjusted via the built-in potentiometer and these DC converters have a 150% peak load capacity. For safety the DDR-120 DC converters have 4KVdc reinforced input / output isolation. 
 
Refer to table below for models in the range:
 
Output
Input
 
DC Voltage
Power
Rated Current
Input Efficiency
Input Voltage
DDR-120A-12
12V
99.6W
0 ~ 8.3A
88.50%
9 ~ 18VDC
DDR-120A-24
24V
100.8W
0 ~ 4.2A
88.50%
9 ~ 18VDC
DDR-120A-48
48VDC
100.8W
0 ~ 2.1A
88.50%
9 ~ 18VDC
DDR-120B-12
12V
120W
0 ~ 10A
89.00%
16.8 ~ 33.6VDC
DDR-120B-24
24V
120W
0 ~ 5A
89.50%
16.8 ~ 33.6VDC
DDR-120B-48
48VDC
120W
0 ~ 2.5A
91.00%
16.8 ~ 33.6VDC
DDR-120C-12
12V
120W
0 ~ 10A
89.50%
33.6 ~ 67.2VDC
DDR-120C-24
24V
120W
0 ~ 5A
91.00%
33.6 ~ 67.2VDC
DDR-120C-48
48VDC
120W
0 ~ 2.5A
92.00%
33.6 ~ 67.2VDC
DDR-120D-12
12V
120W
0 ~ 10A
89.50%
67.2 ~ 154VDC
DDR-120D-24
24V
120W
0 ~ 5A
91.00%
67.2 ~ 154VDC
DDR-120D-48
48VDC
120W
0 ~ 2.5A
91.50%
67.2 ~ 154VDC