Is that Vienna, Austria or Vienna, Illinois, USA?
I know nothing about that circuit board. However,
before replacing the diodes you should first
determine what caused them to burn out. It's
not that common. There may have been a wire
that shorted to ground or touched some metal
part that is grounded. Since the loco operates with
the lights turned off, that seems to indicate a
short in the light wiring.
What type of lights are on the loco, incandescent or LED?
Once you find what caused the issue, you could take
the board to an electronics parts store and should
be able to find replacements. The amperage capability
is the most important spec for a diode.