Especially if Mexico agrees it would be okay.

That is generally complicated territory when you attack terrorist/revolutionary groups not affiliated with the state, especially when the latter lost control over the territory those groups are residing in.

But Mexico could do the same with US gangs basically if the US does that one-sidedly. And Mexicans might not like such interventions from the US. After all there is a bad history of legal and illegal US immigrants stealing Mexican territory. Coincidentally that’s also the US state that complains most about Mexican immigrants

Reading a few articles about this, it seems a big concern is area. They wanna squeeze them in every free space they have between and around roads. Conveyor belts can probably do a lot sharper curves etc. than railways. If they do special small rails, they’ll also need special trains for that.

From the articles it’s also not clear if it’s from one point to another point or from multiple to multiple. They talk about deliveries, which would rather be multi to multi, but it’s not explicitly mentioned anywhere.