Coming from a transport modeller, the title of this article is incredibly flawed, and the write up should row back a bit.
The study itself seems great; looking in detail at the carbon cost of a transport mode throughout its lifecycle. However, it emphatically shouldn't be used to inform transport policy on its own.
This will have a focus on the UK, as this is what I'm familiar with.
Rail schemes, particularly heavy rail, has massively high start up costs due to all the engineering that has to go in place (because if rail goes wrong, it tends to go very wrong, and so the rail industry and legislation is naturally very cautious).
We don't just need to get to net zero; we need to get to net zero fast. Bus rapid transit is much faster to get off the ground, and can be electrified by putting batteries in and having quick charging at certain stops and, crucially, has a capx that a cash strapped local government is more likely to swallow.
Really interesting -- thanks for sharing!