Railway or Railways Minister?

A huge network which carries people and freight across India is the Indian Railways, that is Railway with an 's' attached. Like the plural of the word.

The minister in charge of that department is almost always referred to as the Railway minister. The 's' is missing.

Shouldn't it be the Railways Minister?

The annual budget he or she presents to the Parliament is, again, most often, the Railway Budget, not the Railways Budget. 

Even the Indian Railways uses it as a singular on its portal where the budget is uploaded, and headlined the 2013 budget as the 'Railway Budget' - the 's' missing. Some newspapers trim it to Rail Budget.

However, some newspapers, do use it in the correct form but only occasionally.

Makes one wonder, which is right - the one in popular usage or the way the Indian railways calls itself?

This confusion is confounded when the entity calls itself 'Bharatiya Rail' as its Hindi version.

There is much confusion at the official level itself. The body, which was later registered under the Indian Companies Act, came to be under the Indian Railways (yes, with that 's'). However, in an amendment to that Act in 1989, the law-makers used both railways and Railway.

The head of the unit that provides the oversight on safety is the Commissioner, Railway Safety, and each of its several zones are only a railway. There is the Central Railway, the Western Railway etc.

Interestingly, the top group that administers the entire network is not the Railways Board but Railway Board.