Sorry, 5jj. I didn't elaborate it. My elaboration with the first special use holds good for this use too. I.e, When we refer to the whole system we say 'the railway', 'the subway' etc, but when we be specific, we say, train, bus and the likes.Special case-2: Use with transportation:
Eg: The railway, the subway etc
We normally go by train, bus, tram, tube etc; we don't use an article.