MetroNorth wants to abandon Beacon Line, remnant of NH Maybrook Line - Trains Magazine

Patterson

The rails are in no condition to support rail traffic. Several of the bridges have had the rails removed. Along the whole length the ties are rotted and on some of the curves you can visually see the rails have started to straighten thenselves. It would take a 100% renewal of the ROW to restore rail service. I do not think that is an investment MNCRR can afford.

This is in the gist of the Housatonic filing, if you look carefully.  They note that minimal, if any, attention has been paid to the portion from Beacon to the Connecticut line, perhaps not since 1995 (which would be borne out by the track condition you observed).

My suspicion is that there isn't, and probably wouldn't, be the money to restore the track to Beacon (and little incentive for MN to do it for their own prospective purposes).  If it were, though, a modern TLM would make reasonably short work of the job, even if some of the subgrade and drainage need remediation or improvement at the same time.

Perhaps the more important issue is the cost for the Danbury to Southeast remediation.  Housatonic owns the line to the 'border' and, presumably, they have kept it in better shape despite having little or no 'through' trackage-rights operation west of there.  The issue then becomes the less than 14 miles from Danbury to Southeast and the junction with the Harlem Line, plus any "passenger-grade" connection onto that line if runthroughs are intended (this almost certainly workable with only one approach quadrant for bidirectional push-pull traffic).  I assume the issue of whether or not to electrify this comparatively short stretch for run-through, now that there is a 'trail in being', is factored adequately into the sensible part of the planning going forward, the consideration for TLMs being the periodically longer tie provision to be made whether or not active third rail is installed at the time.

I continue to think that the 'first best' approach to this is a Connecticut-owned shuttle, more a railbus than a full car or train, with MN trackage rights west of the line.  That eliminates many of the concerns with equipment proximity to hikers, Metro-North equipment use and crew concerns over state boundaries, having two different sets of destination out of GCT (or longer routes via Danbury in and out), and service vs. equipment cost concerns.  What this does not address is the cost split to renovate the track between Danbury and Southeast, which would only be on a 'pro rata' basis if an adequate return (or proportional subsidy) were provided to New York since the real proximate benefits are to Connecticut.