rail has 12 distinct synonyms spread across 8 of its 15 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
provide with rails
“The yard was railed”
convey (goods etc.) by rails
“fresh fruit are railed from Italy to Belgium”
lay with rails
“hundreds of miles were railed out here”
fish with a handline over the rails of a boat
“They are railing for fresh fish”
spread negative information about
“The Nazi propaganda vilified the Jews”
short for railway
Synonyms, antonyms and the broader and narrower relations for rail come from Princeton University’s WordNet. Full sources and licences.
“he traveled by rail”
a bar or pair of parallel bars of rolled steel making the railway along which railroad cars or other vehicles can roll
a horizontal bar (usually of wood or metal)
any of numerous widely distributed small wading birds of the family Rallidae having short wings and very long toes for running on soft mud