'miles of track' is correct and usable in written English.
You could use it to refer to an extensive length of railroad track for example: The freight train rides over hundreds of miles of track.
Eight miles of track in all.
HOW many miles of track does the city subway have?
Seattle is turning 13 miles of track into bike trails.
In 2001 it had 33 miles of track.
He was refurbishing a hundred train stations, rebuilding miles of track.
They destroyed miles of track by heating the rails and bending them around trees.
The combined company will run 111 railroads covering more than 15,120 miles of track.
"It's twice as expensive — for only 20 miles of track — as the Washington Metro".
Construction required 118,597 tons of steel to create the superstructure and 33 miles of track.
The first 29 miles of track, between Madera and Fresno, will still be laid as planned.
The railroad also needs to install 162 miles of concrete ties and replace 270 miles of track on the 1,900 miles of track it owns.
