When Irkutsk was gained, the first serious troubles arising from the mountains confronted the engineers. The survey showed that the line here would have to describe a huge detour to round the southern extremity of Lake Baikal, a sheet of water as large as England. The country was broken up to an extreme degree, and among other works of a heavy nature involved was a tunnel nearly 12,500 feet long through the Zyrkousounsk mountain chain, which towers to a height of 12,000 feet above sea-level. But the tunnel was only one obstacle which would have to be overcome, for heavy cuttings through rock and big fills to cross depressions were indicated on all sides. Some idea of the outlook was afforded from the estimated cost of this 182 miles of line which was ciphered at £2,700,000, or $13,500,000. As, after compassing the lake, the line swung sharply north-eastwards to gain Myssovaia, practically opposite the point on the west bank, a bold temporary expedient was suggested. This was the installation of a large vessel combining the features of an ice-breaker and ferry, which should carry the trains intact across the lake, a distance of about 45 miles. By this means construction from the eastern bank could be hastened, leaving the line around the end of the sheet of water to be built at leisure at a subsequent date. The construction of this vessel was entrusted to Sir W. G. Armstrong, Whitworth & Co., Limited, who had undertaken the ice-breaker _Ermak_ which had proved such a unique success in the Baltic Sea. It measures 280 feet in length and has a displacement of 4,200 tons. It is propelled by twin screws driven by triple expansion engines developing 3,750 horse-power. A third screw is placed in the front, which not only serves to assist propulsion, but also to crush the ice, the vessel, as it were, cutting its own channel. Rails are laid upon the deck of this steamer so that the train, when it comes to the water’s edge on one bank, proceeds under its own power on to the steamer, and upon reaching the opposite bank of the lake runs on to dry land. In addition, there is accommodation for a large number of passengers. The vessel was built on the Tyne and then dismantled, every part being numbered to show its relative position. It was shipped to St. Petersburg, and from that point dispatched to Krasnoiarsk. Here on the shores of Lake Baikal the parts were reassembled and the vessel was launched. This ship-building operation was no mean feat in itself, bearing in mind the remote situation of the lake and the complete absence of those thousand-and-one facilities which are to be found in a shipyard on the Tyne.