so the way i understand it, at first refinery strikes had little impact because other refineries still had slack capacity. but even before that slack capacity was gone, it had a further effect that now fuel was not prepared in places it used to be, so it had to be hauled longer distances. meaning logistics is strained and some fuel is used to haul it, and also now fuel production is more concentrated
at some point that slack capacity was gone and fuel went from not where you need it to not existing at all. there already were shortages in some regions. that and still large demand for fuel for farming caused decrease in exports. there was a refinery that only produces products for export, and its output wouldn't be directly usable as fuel (they only distilled crude into fractions, still high in sulfur etc) but it was also hit so exports from it don't matter because these are none
at any rate these developments are on borrowed time because it only takes maybe half year to repair more advanced parts of refinery, so under certain droning intensity they can just roll on. everyone involved knows that, and looks like situation will get worse for russians
Trains (electric) or pipelines generally won't, but pipelines aren't everywhere you need them and trains can't be used for anything else in this case. Effect is the same: local shortages