Quite fascinating, I had I thought read what there was to read on the Lyons branch, not that there is much but had not heard of Mason Bogies operating on it.

I had come to the conclusion that availability was a major factor in going with Mason Bogies for the South Park, the ability to go around tight bends seems to have been overstated.

None of them lasted very long, I assume their design made them more in need of heavy maintenance and were the first ones to be economically worn out.

They did use Shays up to Lyons, most of the business came from the stone quarries which may explain the switching reference.