[2] At Blaenau Ffestiniog it made a direct connection with the Festiniog Railway (FR) with which it was closely associated during its fifteen-year life.

The promoters owned the land on which the line was built, so no parliamentary process was needed to incorporate the company or proceed with building, though the operators sought and obtained Board of Trade inspection before opening as if that were a statutory requirement.

[4] In practice the tolerances were sufficiently wide to allow Festiniog Railway locomotives and rolling stock to use the line, but there is no record of F&BR stock venturing onto FR metals other than transit to Minffordd when their two locomotives made rare visits to Wolverhampton for heavy repair.

[6] The quarries at Blaenau were connected to the harbour at Porthmadog by the recently built Festiniog Railway (FR) and as a result were able to significantly increase their output and profitability.

However, the FR was struggling to cope ("hopelessly overburdened" according to the standard work on the F&BR[6]) with the volume of traffic from the quarries and some owners – notably Samuel Holland, later to be a local MP – were looking for other outlets for their product at lower charges.

At the same time, several standard gauge railway companies were looking to extend their lines into the region to tap the demand for slate transport.

The quarries around Tanymanod - especially Craig Ddu - were not rail connected and were on the proposed route of a northward extension of the Corwen and Bala Railway.

That line would have continued from Llan Ffestiniog to a junction just north of Talsarnau, but no construction ever happened, "the threat of it had played its part".

[8] The prospectus made brief mention of the line being able to use the FR to "command a very large traffic in goods", but saved its most lavish imprecations for the passenger potential, notably for workmen ("very great") and tourists ("immense").

[9] Although initially promoted as, in effect, a branch of the FR, the F&BR was built on a formation that was designed to be easily converted to standard gauge if and when an extension from the Corwen and Bala Railway approached from the south.

[12] Some bridges were erected during the line's later narrow gauge years and on conversion, using metal parapets pre-cast at the Brymbo Foundry.

The Board of Trade followed up on 5 June, informing the company that it had no objection to opening for public traffic, though in fact a passenger service had started on 30 May anyway.

A rock fall struck a passing train in 1878[21] and carriages were blown over in traffic in 1870[22] and 1881,[23] fortunately none of these incidents caused injury.

At that time the directors were aware that they would face significant expenses for renewals before long and in July 1876 struck a prudent deal with the Bala and Festiniog Railway (and behind them, the GWR) who would approach from the southeast, the essence of which was that the Bala & Festiniog would buy the F&BR for £14,000 within three years, take up the B&FR shares and pay the F&BR 5% per annum on the £14,000 until the sale was closed.

William Davies of Cae'r Blaidd, the F&BR Manager, was appointed Liquidator; he reported his work complete on 21 April 1884.

[36] The formal standard gauge opening was on 10 September 1883, at which time the physical Festiniog and Blaenau Railway ceased to exist.

There were differences in location and names between narrow and standard gauge stations: Published photographs[44][45] and a Duffws Signalbox diagram[46] show signals at Diphwys (F&BR), Tan-y-Manod, Tyddyngwyn and Festiniog.

From at least 1874, BoT records show the line was operated on the "One engine in steam" method, which contradicts the 1868 Board of Trade's insistence that there be Train staff working.

It is possible that trains were admitted to the line using the Festiniog's equipment, then run as sole occupants of the route, with points being operated by hand.

C. M. Holland made a virtue of their low height, as the wheels were recessed under the seats, giving a lower centre of gravity, smoother ride and more headroom.