There's not a lot of places in the country with "true" interstate integrated transit needs. Places like Chicago have far suburbs and exurbs within the commute shed in other states but are still generally within state. Even cities like St. Louis generally have a clear dominant locus in one state, which limits the ability of the other state(s) to play off the other state.

The general exceptions to this rule are Kansas City and Washington, DC, where the workplace loci are truly distributed among multiple jurisdictions so that no one state is dominant. In DC, the standard subway (WMATA) runs across all three jurisdictions, although there is some amount of political football over funding. The commuter rail systems are not integrated, but that is largely due to limited capacity over the Long Bridge. (MARC, the Maryland system, is participating in the Long Bridge replacement project in part because they do intend to extend service to Alexandria once there's capacity to do so).

NYC is a truly special case because it's simply so massive. In terms of geographical boundaries, there are roughly three natural independent sheds: trans-Hudson, trans-East, and trans-Harlem rivers. Each of these sheds is massive enough to let each of the three commuter systems that focus on their own sheds to not have to coordinate. These sheds also happen to largely coincide with different states: NJ is trans-Hudson, NY (or, rather, Long Island) is trans-East, and CT (as well as parts of NY) is trans-Harlem.

Even in DC, there is a lot of public transit not managed by WMATA. While WMATA runs the MetroBus system, each jurisdiction also has its own bus system beyond that, in part because none of the jurisdictions wants to have to negotiate with all their neighbors to make service changes to routes that start and end within their own borders.

DC's MetroRail system has a very large share of rides that begin in one jurisdiction and end in another, so it makes a lot of sense for it all to be managed centrally by WMATA. But I suspect there aren't a lot of commuter train rides that begin in Connecticut and end in Suffolk County (or that start in Baltimore and end in Prince William County). Given that, just how would a MetroNorth/LIRR merger help riders?

The main benefit from the proposed merger would be solving issues with Penn Station: you could eliminate some of the separate concourses, easing overcrowding; by through-running trains, you could also increase the number of trains serviced without having to build an expensive new station.

Sure, agencies are created whenever multiple states need to share two sides of a public transit solution (or bridges, tunnels, etc.). e.g., Port Authority of NY & NJ, PATH, Delaware River Port Authority (PA & NJ), etc.. they are found virtually everywhere where cities exist near borders.

I should have clarified. I was talking about public transport specifally for light rail. The article was about subways specifically.

NJ Transit and SEPTA share the link between Trenton and Philadelphia. Metro-North and NJ Transit also have shared service into upstate regions of New York on two lines.

> Does any cross state combined public transit effort even exist in the US?

Yes, AMTRAK [0]

[0] https://history.amtrak.com/amtraks-history/historic-timeline

Amtrak is the federal government. I am talking about one states public rail system connecting with another states rail system. New York to New Jersey was given as an example in the parent post.

Amtrak is great for vacations or other travel but I don’t thinks its use case is daily commuters. At least it’s not the use case for the majority of the US.

The Amtrak Cascades line is actually state owned and operated: http://www.amtrakcascades.com/about One example, at least!

Chicago's Regional Transit Authority operates the Metra which spreads into northern Indiana and Southern Wisconsin

> Metra which spreads into northern Indiana

You're thinking of the South Shore Line [0], which is entirely independent of Metra [1] and the RTA.

> and Southern Wisconsin

Metra has just one stop on one line in Wisconsin (Kenosha on the Union Pacific North line).

[0]: http://www.mysouthshoreline.com/

[1]: https://metrarail.com/maps-schedules/system-map

You are correct, but the planned extension of the CTA Red Line includes a new station that is shared with the South Shore, creating a brand-new connection ability that never existed before. The planning for the new Union Station to McCormick Place link involves connecting the CTA, Metra and South Shore lines.

If you are standing in downtown Chicago, you can jump onto a train and conveniently go to O'Hare International (Blue Line CTA), Midway International (Orange Line CTA), Milwaukee International (Amtrak), and South Bend Regional (South Shore). South Bend has daily non-stops to NYC so I'm not sure why it's called a regional airport, but, well, there you go.

I'm confused by what possible efficiencies can be generated by connecting the Red Line and the South Shore line. I presume that most riders on the SS line are commuting to work in or near the Loop. The SS line is undoubtedly faster than the Red Line. Furthermore, there's already Metra lines in existence around the area of the proposed Red Line extension.

Furthermore, I'm not sure what good a Union Station to McCormick Place link would do. Union Station is already within a 20 minute walk to every single CTA/Metra/SS line. Furthermore no one really lives/works near McCormick Place. It's primarily a convention center.

It has an express, and it still counts.

Although it really sucks when someone misses the correct train and you have to drive to Winthrop Harbor to pick them up.