If the VHS and MHS route share the same corridor, that has to be a new alignment ... at least in the parts of the country where VHS routes will be most lucrative.

If VHS routes in the US are laid out so that the corridor also runs through towns that are the target for MHS interurbans, that means a substantial reduction in the effective trip speed of the VHS route as it deviates further and further from the direct route between its target markets ... and also as it makes accommodation for the existing built environment.

And meanwhile in many areas of the country there are freight corridors in use that were allocated to serve dual track systems and are in use by single-track plus passing loop systems. Because of the byzantine complexity of the access rights on the corridor ... strategic parcels that were bought outright, easements, perpetual roll-over leases, etc. ... the owners of those access rights rarely narrowed the corridor when they switched to single track ... that normally does not happen unless the entire corridor has been abandoned (and sometimes not even then ... it can sometimes take a while for an abandoned route to make its way through the system and lose its corridor status).

And because of the time that they were laid out and their importance in the development of population centers, they often run exactly where we would want an interurban branch line to run. That is especially the case for Dixie and the Great Lakes States, which are politically critical to ensuring the an expanded passenger rail system is not seen as a pure subsidy to the "urban east coast".

Get an new track on that system that relies on stretches of the freight track for its passing loops, and enact priority for the passenger services, and you have a substantial savings compared to the cost of acquiring the right of way for a new alignment.

And, as in the above thread, that is not the conditions that are in place in another area, then don't do it there.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.