Ahh yes. I've oft thought of the FS&K as "The SNE of the North"
but from a much earlier date than the Titanic.
While the reason is not stated quite so directly in Lowenthal's volume, (which I am currently enmired in at this time,) the reason for the stoppage of work less than a year after it began was more to do with economics and back-room politics than anything else. The man who perished on the ill-fated liner was Charles Melville Hayes, and he was succeeded by a man named Chamberlain who had acquaintance with Charles S. Mellen of New Haven, B&M and Maine Central fame some time before he (Chamberlain) rose to control the GT. Seems they were close to making a deal for traffic rights over each other's lines just about the time Chamberlain called a halt to the SNE's construction.
The reasons for the subsequent continuation of construction nearly a year later was purely political! While Mellen's reign as the Rail Lord of New England was rife with scandal, the GT sought to distance itself from such and set out to complete the project rather than be drug down with Mellen and the New Haven et all.
It was WW1 and subsequently the Great Depression that finally killed the project.
I have, as I've been reading, been out to many sites along the SNE, as well as it's twin cousin the Hampden RR which also started from Palmer but went toward Springfield to parallel the B&A and funnel traffic from Western New England over the NH and the B&M into North Station. This line was made 100% complete and even had an inspection train run over it's entire length before it was abandoned, never to turn a wheel of revenue. The similarities and coincidences of the two lines are amazing, and it is easy to see why even today one is mistook for the other.
Case in point, I was walking the old OOS Central Mass line in search of the spot where the Hampden would have crossed it and encountered a woman leading a girl on horseback along the track. She referred to the Hampden RR as "The Grand Trunk," even after I had told her the GT/SNE was in the next valley over toward Brimfield.
It has been an amazing journey of discovery finding and photographing the old concrete monuments to engineering and faded dreams. They are truly remnants (as Mr Lowenthal himself put it,) of a lost civilization like unto the pyramids.