Wiktionary
n. (context railroads English) A secondary railroad route or one subsidiary to a railroad's main lines.
WordNet
n. a railway line connected to a trunk line [syn: spur track, spur]
Wikipedia
A branch line is a secondary railway line which branches off a more important through route, usually a main line. A very short branch line may be called a spur line. David Blyth Hanna, the first president of the Canadian National Railway, said that although most branch lines cannot pay for themselves, they are essential to make main lines pay.
Usage examples of "branch line".
According to the maps of Grantville, we don't have a direct branch line to the mine.
He described how two trains on the Millfield Branch line had been switched on to the same station by mistake.
For as far as they could see, the thin silver line of the rails spun on towards the horizon with only an occasional break, marked by a points lever, where a rusty branch line curved off into the dark mass of the Spectre Mountains on their right.
There's a Southern Pacific branch line in through McMinnville and he's done better at keeping up the bridges than we have.
Greenfield has been camping on my trail for three months, wanting us to build them a branch line.
At Callyan they reached the junction of the branch line which descends towards south-eastern India by Kandallah and Pounah.