Ok, firstly sorry if my typing is wierd, I am stranded and using my iPhone

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Well here's the deal, I went to pick my mother up frm the station and now we are stranded at the station.
As I was leaving I noticed he car was idling roughly, and as I arrived I noticed the engine temp almost hitting the red!
Luckily I hAd enough time to safely park, but I don't know what's wrong.
Firstly, how long should I wait till it's safe to check my radiator coolant?
Secondly, what else should I check?
Thanks 4 the help.