A history of the Berkshire Line
Here is Chapter 4 Berkshire Line: New Haven's Route to the Hills, pages 45-53, from the book New Haven Passenger Trains by Peter E. Lynch, published by Quarto Publishing Group USA, 2005. Here's a bit from the introduction: The Berkshire Line originated as the combination of the Housatonic Railroad, which opened between Bridgeport and Canaan, Connecticut, [...]