Tom, the test of CLRVs in Boston did not result in an order for cars of the same type, true, but I do not believe the intent was ever to purchase "off the shelf" CLRVs. What the tests intended to do was give the MBTA quite a bit of data that later helped them develop the specifications for Boston's Type 7 cars, which are very similar to CLRVs and ALRVs in many ways, and have been (except for an unfortunately high number lost to wrecks) very successful.
CLRVs might have been a good fit for the Mattapan Line, but with ten cars rostered for the line and only six required for peak service, a small order for just that one line would not have been cost effective. The PCCs could be rebuilt cheaper, and they endure on the Mattapan Line largely because there was (still is, as far as I know) no substation solely providing power to the Mattapan Line. Type 7s cannot run there - they draw too much power. The Mattapan Line was(is?) fed off the nearest Red Line substation, which is up around Fields Corner. I admit this may have changed, because now that there is apparently enough juice available to equip the PCCs with air conditioning units. But that has been a recent development.
CLRVs and ALRVs were, truly, the PCCs of their time. Simple, rugged, and effective. Not sure why that idea didn't take off more than it did (the only other taker was heavily modified ALRVs in San Jose, many of which are since retired). I have rode many miles (sorry, kilometers) on CLRVs and ALRVs in your home city. But like our far less successful Boeing cars, some of which we patched up and somehow got close to 30 years out of, the CLRV and ALRV fleet is finally beginning to show its age (they're getting close to thirty years old too!). Wonder if the MBTA would consider picking up number of them, rebuilding and refurbishing them, and replacing the PCCs with CLRVs?
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