Fact ... In the late 1840's rail services were expanding in the White Mountains and Upper Connecticut Valley. The White Mountain RR started building south from Groveton NH where it connected with the then broad gauge Atlantic & St Laurence Ry (the forerunner of the Grand Trunk Ry). Financially troubled from the start it leased the part of the proposed line to the Boston Concord & Montreal (one of the principle fore-runners of the Boston & Maine), who started at the southern end and worked north reaching Littleton NH by 1853. The WMRR didn't manage to get to Lancaster NH until 1870.

And this is where semi-fiction takes over ... The BC&M tried to extend into the White Mountains towards Mt Washington against which the Portland & Ogdenburg successfully petitioned in the courts. The BC&M had tied itself in legal knots over the proposed extension and lost interest in the WMRR for the time being, surrendering its lease as part of the court settlement. The P&O was ready to jump into the breach, leasing the whole of the WMRR in 1875. The upper reaches of the WM had some good logging railroads and mills as customers, who's products would find ready markets in coastal Portland and good revenue for the P&O into the bargain. The P&O completed the link between Lancaster and Littleton while it was still completing its own mainline to St Johnsbury VT in 1877. By 1880 it was obvious that the P&O had over-stretched itself financially and the whole shooting match was leased to the MEC with shareholders blessing.
The B&M hadn't finished trying to expand into the area, however, and one of the logging lines, a 3-footer, the Whitefield & Jefferson RR was rebuilt to standard gauge with the B&M very much holding the purse strings. The reason for expansion was not so much freight revenues, which of course were still very lucrative in the 1880's, but summer tourist traffic. There were many resort hotels springing up in a late Victorian fascination with nature, naturally the B&M was involved in promoting some of these resorts. In 1895 B&M took a lease on the W&JRR and set about extending it towards productive timber mills in Berlin NH. The B&M managed to negotiate limited running rights over the MEC run WM between Johnsboro NH to connect its otherwise isolated outpost at Whitefield.