Under-investment ... absolutely there is.
The other half is sorting out the perverse tax incentives that favour cars and trucks. A level playing field for all modes of transport.
Remove the tax incentives . I am not saying impose NEW taxes, just make ALL car and truck use the same.
Case in point: In Australia, all Diesel purchases are taxed. However, farmers may directly claim that back. And the Diesel fuel excise it fed directly back in to roads. However, who is the single biggest purchaser of Diesel fuel? In the state of Victoria, that would be the regional train network.
In fact, that's highly representative of the thinking of modern governments. The train network needs the diesel because they can't fund the capital intensive electrification, and end up paying more for the fuel they do use. Which is is then fed back in to the competition.
My guess is that nearly every country has these types of stories. Many, many times.
And then I would fix the accounting around road-building as well. That's a classic case of where the costs are socialised, but the profits are privatised. Full cost recovery for the road network - you know that means tolling. Even the little ones. Suddenly, the rail networks of the world don't look so expensive anymore. This being politically impossible in some countries means it will be a footnote to an asterix to a spec of dust in history.