It would spend the remaining 42 year of its existence in receivership or trusteeship: one of the longest bankruptcy proceedings in American railroading history.

Further adding to the confusion is the fact that both were nicknamed the Shawmut Line, both operated in roughly the same geographic area, and both used nearly identical logos during their history.

The expense of connecting the divisions and upgrading the physical plant to handle through coal trains, coupled with the failure of the PS&N's principal bond underwriter, forced the company to declare bankruptcy in 1905.

Coal (bituminous) was the principal commodity for the line during its entire existence, though passenger trains and, after the late 1920s, self-propelled gas-powered motor cars (known on the PS&N as "Hoodlebugs") also ran on the route until they were discontinued in 1935.

At Prosser, passengers traveling the full route south would switch to a motor car in Train 11 southbound (12 northbound) which began its trip on a side branch from Olean.

Portions of the line serving Olean, Brandy Camp, and Farmers Valley were acquired by the Pennsylvania Railroad (the Farmers Valley portion is today owned by the Norfolk Southern Railway and operated by the Western New York and Pennsylvania Railroad).