The tragedy centres on Heracles and his wife Deianeira, who attempts to win back his love from a captured slave with a love-potion, only to find her self tricked into poisoning him.
Free online texts
Gutenberg: The Seven Plays in English Verse, translated by Lewis Campbell. Multiple formats.
Internet Archive: Sophocles Vol. II; Ajax, Electra, Trachiniae, Philoctetes. Greek text with facing translation by F. Storr (Loeb edition, 1916). Multiple formats.
Internet Archive: Sophocles, translated by Thomas Franklin (1848). Multiple formats.
Internet Archive: Sophocles Vol II; Trachinae, Ajax, Philoctetes, Electra, verse translation by Thomas Dale (1824). Multiple formats.
Internet Archive: Sophocles, Vol II; Ajax, Electra, Trachiniae, Philoctetes, Fragments, translated by Lewis Campbell (1879). Multiple formats.
Internet Archive: The Tragedies of Sophocles, translated by Richard C. Jebb (1904). Multiple formats.
Loebulus: L021 - Sophocles II: Ajax. Electra. Trachiniae. Philoctetes. Greek and English parallel text. Loeb edition, PDF format.
University of Adelaide (Internet Archive): The Trachiniae, translated by R.C. Jebb. Multiple formats.
History of Ancient Greece: Sophocles, podcast by Ryan Stitt.
History of Ancient Greece: Heracles from Zero to Hero, podcast by Ryan Stitt.
Librivox: Trachiniai, translated by Lewis Campbell. Public domain audiobook.
The Great Conversation: Further reading at Tom's Learning Notes
Aristotle: The Poetics.
Ancient Greek resources: Learn to read Greek classics in the original.
Bloom's Western Canon: The Women of Trachis is listed.