I have a timetable for a multi day journey train, and I need to calculate
the time to each next stop in hh:mm in column G. In column A is the station
name, column B is the date, column C has the arrival time and column D the
departure time.

Trying to calculate the time to next stop works, unless the train passes
through midnight between stops, so to compensate for this, in column E I
have arrival date and time and in column F departure date and time in a
custom format of dd/mm/yy hh:mm, and the difference in duration between the
two times and dates is thus easily calculated.

These columns I plan to hide when printing as the information is duplicated
in B C and D.

At the moment I have been manually creating a single column of dd/mm/yy
hh:mm from two columns (dd/mm/yy + hh:mm --- dd/mm/yy hh:mm), is there a
quicker way to either perform the time to next station calculation without
the need for the date and time being in the same column, or to quickly
create the date and time combined column from the two separate columns
without having to manually type every one?