The four-track counterfactual leaves a question about the infrastructure supplied with the rails. If Russia still depends on the historical Lake Baikal ferries before the bypass railway exists, four tracks feed into a crossing carrying only one locomotive and its cars at a time. More ferries or larger vessels would be needed to exploit the increased traffic. Supplying the bypass would raise a different engineering problem: four tracks require wider tunnels and more space around the mountains. The route through Moscow also makes this a reconstruction of existing settlements and difficult terrain, with much more to maintain than the rails alone.
Notable Point · 37:31-39:53
Lake Baikal and the limits of a four-track railway
Four tracks cannot deliver their full capacity through a single ferry crossing, while a complete bypass introduces wider tunnels and heavier maintenance demands.