In northern Russia (and to a much lesser degree elsewhere), many communities are only reachable by river. In summer there are scheduled boat services on those rivers (see Overview (map) of Russian long-distance river regular passenger ships in regions too remote for roads or railways), but in winter the rivers turn into ice roads (автозимник) like the Хулга / Khulga.
Are there any scheduled bus routes on any of those those ice roads? I'm mostly interested in buses that run over a river for a large distance, as opposed to just crossing the river where there would be a ferry in summer.
I'm interested in bus services on ice roads in other countries too, but I expect Russia to be the "best bet".