Great line from Eastern queen on upcoming schedule (7)
I believe the answer is:
equator
'great line' is the definition.
'equator' can be an answer for 'line' (equator is a kind of line). I'm not certain of the 'great' bit.
'eastern queen on upcoming schedule' is the wordplay.
'eastern' becomes 'e'.
'queen' becomes 'qu' (abbreviation for queen).
'on upcoming' says the letters should be written in reverse (in a down clue, letters go up).
'schedule' becomes 'rota' (I've seen this before).
'rota' backwards is 'ator'.
'e'+'qu'+'ator'='EQUATOR'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for equator that I've seen before include "Line through Brazil, Kenya, Sumatra" , "Important line" , "Imaginary circle round the earth" , "Earth's north-south dividing line" , "What map line may represent" .)