1) Boston City council may have some legal requirement to make these files available to people with disabilities under some disabilities law. You could contact a group for people with hearing impairment to ask for their advice.

2) I remember when you used to be able to search for a file extension and get useful information. Now I search and I get useless, hopeless, results. Really awful. SEO has poisoned the WWW and search engines are not doing a good enough job of repairing that damage. :-(

2b) Doing a websearch returns many posts made to various forums asking for this media to be made open. Perhaps these are all from the same person on a campaign.

3) You could buy the software, and load the files. (Also, possibly export them to an open format?)

4) You could ask someone at Bountify to create a file-reader for you. (https://bountify.co/) Make sure to leave good information, and an easy link to one of these files.

5) You could ask the makers of the machine to create a simple, limited feature, reader for the files. They don't appear to have one at their website. (http://www.stenograph.com/pages.aspx?docid=757&id=40001)

6) You could investigate Open Source - Plover (http://plover.stenoknight.com/) might be able to convert the software. Or maybe someone could add conversion routines to it.