""I'm surprised you don't know the difference and why it is important. See, Accuracy says: There is a train coming! Pedantry responds: There are two engines.""

So, "There's a train coming" = Accurate
    "There are two engines" = Pedantic

Errr! What do you call it when someone then replies:- "They're not engines, they're Locomotives"?

Don T. :-)