A corridor like this could extend further, especially if it's LRT. (Or could be split between LRT and HRT.)
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A combination of median-running along Burlington Mall Road and the powerline ROW northeast of Exit 51 allows you to connect the Burlington employment center with the intermodal hub at Anderson/Woburn.
The eastern half of this route along the powerline ROW would probably traverse the 3.6 miles non-stop. As a rough estimate, Concord <> Lincoln is 3.4 miles and is traversed by the commuter rail in 6 minutes at an average of 34 mph; LRT has a lower top speed but faster acceleration, so running at 30+ mph seems plausible enough. That would put the travel time through this section at 7 minutes, which is
definitely competitive with a shuttle bus running via the highways (and would have better reliability either way):
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How far you continue the LRT route toward the west depends on which extensions you end up going for on the Minuteman and where you choose to plop the terminus. But an LRT route could
- terminate at Burlington Mall
- continue south down the Minuteman
- continue west to Hanscom via street-running on Hartwell Ave and Barksdale St
- turn northwest and terminate in downtown Bedford (with an extension to Concord if you feel like jousting with the rail trail)
The biggest argument against an Anderson/Woburn <> Burlington Mall LRT line is that, AFAIK, there currently is no bus route between the two. Reverse commuters to Burlington are probably driving or taking the 350. However, increased frequencies on the Lowell Line might change this; today Anderson/Woburn gets 45 min peak/1 hour off-peak frequencies, but in a future where it serves 30-min service to Lowell, 30-min service to Haverhill, plus an additional services layered on top, it would become much friendlier to transit-based reverse commutes.