On rail the largest costs are building and maintaining the rail until you get to very high frequency.

In the cities I've lived, it's not quite that.

Building rail is a lot of dollars, but politicians are often happy to throw money at that problem. It's good for a dozen industries, like construction.

But that money cannot then be used to operate the rail long-term. That burden is on the city entirely.

I've lived in two cities that turned down millions of dollars in federal transit grants because they didn't have the money for maintenance and operation.

Capital costs are paid differently and so we can often safely ignore construction costs as they are a different budget.

Putting maintenance into that capital bucket though is accounting fraud and illegal. If you have a rail line the largest cost is regular maintenance which is based on time not wear until you have a very large number of trains running. So my point stands even if you separate the buckets.