Just for fun, a thought experiment, how much theoretically does it cost to build a commuter rail service? I've lived in a city that has thousands of cars commute to a close by city every day, about 30 miles away. It kills me that there is not an obvious commuter line between them.
There are (I believe) UP tracks there. Not that I have millions of dollars lying around but it did get me thinking, how much really does it cost? For fun, of course, ballparks.
Say end to end, about 30 miles. About 25 off that could be on the existing spur that is there, and then say 5 total to tie the ends to potential stations. Then the cost to build 2 terminal stations and say 2 small ones for towns on the way. Then say a single consist similar to the Coaster trains to just ping pong back and forth.
This to me is the "cheap" option to kickstart some transit in cities, but they always seem to think it's impossible. But how much really is a project like that?
This hugely depends on many factors. What quality should the rail be? Do you transport freight at 30km/h or pasenger rail at 200 km/h? Is there electification involved? How is the soil along the tracks? How many trains of what type do you need? Do you want electric train protection and signaling? How nice do you want the train stops to be? Does it cross property of private individuals that you need to aquire?
I just want to say that this is not really a question that has an answer since it depends on so many factors. You also have to think about regulations for rail traffic. Building a rail line in your backyard isn‘t neary as expensive as one you use commercially because of safety standards you have to comply with, which is a good thing.
Oh and even if you could specify a project, i still would have no clue since i‘m not a project manager nor civil engineer, just interested in rail and trains :D