This tunnel proved a more exacting and troublesome undertaking than either the Gravehals or Reinunga works. The boring was attempted at first on the time system, but the advance was so slow and unsatisfactory that this principle was abandoned. The whole tunnel was then handed over to a contractor, but he found the rock so hard that a piece-work system was instituted. In this arrangement the workmen were stimulated to supreme effort by the offer of tempting premiums. Issuing from this tunnel, there is another descent for some miles, when another ridge intervenes, necessitating a sharp climb of 700 feet, followed by a smart downward run to Roa, where a junction is effected with the Norwegian eastern railway system. Contemporaneously with the building of this line between Vossevangen and Roa, the original section between Bergen and Vossevangen had to be overhauled. The metre gauge was in vogue upon this division, whereas the rest of the line was being built on the standard gauge to secure uniformity with the other lines. Accordingly, the narrow-gauge was replaced by standard-gauge track. The Bergen-Christiania line ranks as one of the most striking pieces of railway engineering in Europe, and testifies to the remarkable skill and dogged perseverance of the Scandinavians in breaking down tremendous obstacles as they arose, with complete success. It is no light undertaking to attempt such an enterprise as this in such a latitude across a terribly exposed, storm-swept plateau, among the most sparsely populated regions of Europe, and where the winter lasts for eight or nine months. The rainfall is tropical in its severity, while the storms are of terrific fury, as the workmen found to their cost. Some idea of the magnitude of the work consummated by the engineers may be gathered from a few general details. The line passes through no less than 184 tunnels, which represent an aggregate length of nearly 24 miles. To carry the line across depressions which could not be filled, 14 bridges, ranging from a single-span stone structure of 60 feet to a metal bridge 566 feet from end to end, had to be built. Between the two terminal points 55 stations and stopping-places have been provided. In order to fashion the permanent way the engineers had to excavate about 35,000,000 cubic feet of earth, and nearly 30,000,000 cubic feet of rock on the highest parts of the mountain section, this latter task being assisted by the expenditure of over 1,800,000 pounds of dynamite.