2 Trains


A Train enters a tunnel at 7 o'clock, another train enters the exact same 
tunnel, also at 7 o'clock on the same day. The tunnel only has one track, 
and no other means for the trains to pass, around, over, or under. However, 
both trains made it to the other end of the tunnel untouched. 
How could this be?
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Answer:
One entered at 7 a.m. the other at 7 p.m.