The train just arrived at platform six is the delayed 13.15 from Hereford.
Q; In the above sentence, I assume "13.15" means hour and minute. But do you think writing hour and minute like this is right?
Assuming the question is over how to write and punctuate the time, Cambridge dictionaries say either a full stop or colon can be used: Punctuation, from English Grammar Today. The Guardian style guide recommends full stops with 24 hour times (this does not mean other forms are wrong, only that it wants its journalists to use them). Both sources state that "13.15" is correct.