Race Comment Explainer

Original comment with matches highlighted:

slowly away, towards rear on outside, some t, tail 7f out, 4f out,

Matched phrases & meanings

Phrase	Meaning
Towards rear	Running near the back of the field.
tailed off	A definitive statement that the horse was finished and effectively out of the race
Weakened	The horse lost speed and dropped back through the field.
Headway	The horse was moving up through the field.

Summary

Running near the back of the field.
A definitive statement that the horse was finished and effectively out of the race
The horse lost speed and dropped back through the field.
The horse was moving up through the field.