The most common and most likely answer to this crossword clue is the 4 letter word WAKE
I've seen this crossword clue in The Times
W
A
K
E
More clues leading to the result WAKE
Buddy explains!

The straight part
We know that "Come to/main track" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case come to/main track = wake.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does WAKE mean?
WAKE noun- The act of waking, or state of being awake.
- The state of forbearing sleep, especially for solemn or festive purposes; a vigil.
- (often followed by up) To stop sleeping.
- (often followed by up) To make somebody stop sleeping; to rouse from sleep.
- To put in motion or action; to arouse; to excite.
- To be excited or roused up; to be stirred up from a dormant, torpid, or inactive state; to be active.
- To lay out a body prior to burial in order to allow family and friends to pay their last respects.
- To watch, or sit up with, at night, as a dead body.
- To be or remain awake; not to sleep.
- To be alert; to keep watch
- To sit up late for festive purposes; to hold a night revel.
- A period after a person's death before or after the body is buried, cremated, etc.; in some cultures accompanied by a party and/or collectively sorting through the deceased's personal effects.
- (Church of England) An annual parish festival formerly held in commemoration of the dedication of a church. Originally, prayers were said on the evening preceding, and hymns were sung during the night, in the church; subsequently, these vigils were discontinued, and the day itself, often with succeeding days, was occupied in rural pastimes and exercises, attended by eating and drinking.
- A number of vultures assembled together.
- The path left behind a ship on the surface of the water.
- The turbulent air left behind a flying aircraft.
- The area behind something, typically a rapidly moving object.