Jan 16 (Reuters) - Colonial Pipeline has made progress

in identifying the source of a leak on its main gasoline artery

and estimates Line 1 will restart on Friday, earlier than

previous expectations, the company said on Thursday.

Line 1, one of two mainlines on the more than 5,500-mile

(8,850-km) Colonial system, was shut on Monday night after

Colonial received reports of a gasoline release in Paulding

County, Georgia.

The company earlier expected the line, which supplies about

half of the U.S. East Coast's demand for motor fuel, would

remain shut through Friday.

"On-site work to identify the source of a release and begin

repairs on our gasoline pipeline, Line 1, in Paulding County,

Ga., have progressed," Colonial Pipeline said in a statement on

Thursday.

The line should restart on Friday if site conditions remain

stable and repairs proceed as planned, the statement added,

without providing a specific time.

The restart is currently expected to be at 8 a.m.

Central Time (1400 GMT), a person familiar with the matter said.

A spokesperson for the company declined to answer

questions about the cause and size of the leak.

Line 1 delivers 1.5 million barrels of gasoline each day

from Houston, Texas, to storage tanks in Greensboro, North

Carolina, from where the motor fuel is distributed locally or

shipped to other markets all the way up to the New York Harbor.

It is almost always chock-full of gasoline, making it one of

the most crucial parts of the domestic U.S. gasoline supply

chain.