It's true that property taxes are based on the assessment of a home, but it's also not necessarily true that the assessment does a good enough approximation to consider that any house within 1mi of the train is worth 20% more than one 1.5mi away. From my hobby of looking at home appraisals in Boston towns it seems the biggest factor in most towns is square footage.

Another point to consider is that most towns in Massachusetts seem to use replacement cost as the main method of appraisal versus potential income/value. Meaning, 2 families appraise for nearly the same as a single family when they are in reality worth 1.5-2x more in potential income via rent or selling.