To extend your analogy, it might be a terrible idea to start doing maintenance on a single line track that sees high usage in a holiday season just before those holidays where everyone wants to get away or get home as do your staff. So you might implement what is usually called a change freeze.
On the other hand you might have a different time where demand is low. Shutting down the line if it comes to that will annoy some people but not as many. So you plan your maintenance then and have people ready in case things go wrong.
Software is cheap to produce and quick to change. Building a "third track" on the fly, as needed, is exactly the kind of thing we can do that actual engineers can't. They probably wish they had the ability to do things like that.
This might make sense for your inner city loop, with trains passing by every 30 seconds (and it's gonna help when one train inevitably breaks down). However, it's a totally unreasonable cost for a station deep in the country where trains only stop 4 times a day.