Either of the pair of rails on which a railway train runs.(noun)
A pair of such rails; a railway track(noun)
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Use "railway line" in a sentence
"Next morning we catch a bus that follows the railway line a few miles out of town to the remote hamlet of Ustianova."
"At Ustianova there is nothing but a bar in a wooden hut beside the railway line and a drunk teetering about outside and peeing behind it."
"Hard by one of these were the offices of the Hawker Aircraft company, on Canbury Park Road, a dingy street in Kingston near the railway line where the Waterloo trains rattled past."