At a meeting of the Trans-Siberian Committee in the spring of 1898, the Tsar declared that new surveys were to be undertaken without delay. Concluded in the following year, they confirmed that between Irkutsk and Kultuk was the most difficult terrain to be encountered.
East of Kultuk there were fewer obstacles, therefore an immediate start on this stretch of slightly more than 100 miles was authorized. Four possible routes through the formidable Irkutsk-to-Kultuk terrain were mapped out. It was left to the eminent Professor Ivan Mushketov from the University of St Petersburg to make the final decision. After more than a year of field work, he produced a stack of technical evidence that convinced the committee to follow the [V 010 / P 034 / lake shore] from Port Baikal to Kultuk.
Private Russian contractors, who readily agreed to take the job now that men and equipment could be transported by rail, began work on the Port Baikal-Kultuk section in 1901. Almost 10,000 Italian, Persian, Russian and Turkish workers were recruited together with a garrison of tough Circassian guards.
This segment "surpassed in difficulty and amount of work all those constructed in the Russian empire up to the present." Contractors were forced to dynamite cuttings through [V 004 / mountain folds] that fell sheer into the water, to bore 33 [V 006 / tunnels], and build up embankments with an average of 101,720 cubic yards of soil and stone per mile. Inlets, gorges and Lake Baikal's tributaries required more than 200 bridges and trestles. Much of the route was inaccessible by road and could only be reached by water in those brief periods when the lake was relatively calm and free of fog.
After Japan's devastating torpedo-boat attack against the Russian naval squadron at Port Arthur, the contractors worked at a furious pace to complete the line. In mid-September of 1904, they turned it over to the Ministry of Ways of Communication with so many defects that the first test train derailed 10 times and failed to pass through one of the tunnels until the roof ventilators on the railcars were removed, taking three days to reach Port Baikal from Kultuk. Nevertheless, an inspection team officially opened the long-deferred Loop on September 25.
