Translation:It is half past four, you are missing the train!
The difference being when Germans say "half 4" they mean 3:30. In some places we say "half 4" to mean half past 4, but take out the "past" for ease of saying. Maybe it's a British thingy..
I realise you can't fit all variations in, but FYI here's a definition from Oxford: "half one (or two etc.) informal way of saying half past one."
( Phrases, number 6 http://www.oxforddictionaries.com/definition/english/half#half__33)