Thanks for that bit of info. We had been wondering in an earlier thread if one of the clocks might indicate Greenwich Mean Time. But the use of the two types of clock seems to imply they would normally indicate the same time, with the mechanical clock as a back-up in case the electric one failed. That is my take on it anyhow.
I assume the clocks seen in the Belgenland engine room photo would also be one electric and one mechanical, as they are slightly different in appearance.