I don’t see how you go from that to a comparison against literally the most expensive road tunnel in US history, especially given that the whole point of the silver line example is that it runs through the exurbs on an existing freeway median.
I'm not intimately familiar with the project (and had to ask you which specifically you'd meant), and you failed to adequately develop your argument between sly ad homs.
I'm proposing that land aquisition, as a net factor -- fighting NIMBY battles, as an example, would be a component -- is one of at least three factors disadvantaging rail vs highway construction in the US.
And yet despite this, your own cherry-picked example comes out far ahead, even allowing for what I'd noted were rough and likely advantageous numbers, than a contemporaneous urban highway project. You've not presented much by way of numbers or cites yourself.
If you don't mind a personal observation: you come across, repeatedly and not only with me, as so bent on burying your counterparties that you constantly shift burdens of proof, fail to construct or support your arguments sufficiently, or care to accidentally learn anything along the way. I honestly didn'y know how the Silver vs. Dig comparison would turn out. I simply followed the maths to their conclusion.
A better point of comparison to the Silver Line is the inter-county connector in MD. Both built in the 2010s. $127 million per mile, which includes land acquisition costs because it wasn’t built along an existing right of way like the Silver Line.
You’re also completely off on the ridership side. Because rail only takes you on inflexible routes, actual ridership is low except in dense downtown cores. The Silver Line operates nowhere near capacity. Silver Line ridership is under 17,000 passengers per day. The inter county connector averages 30-40,000. So more than double the ridership for half the per mile cost.