Green’s Dictionary of Slang

derail n.

1. (US campus) an unpopular student [HDAS, citing Weseen, Dict. of American Sl. (1934), suggests that this may be a mis-reading, but it may equally be be a separate or fig./ext. use of sense 2].

[US]M.C. McPhee ‘College Sl.’ in AS III:2 132: His inferiority is further emphasized when he is called: ‘a de-rail,’ ‘a dumb-bell,’ ‘a dumb-rock,’ ‘a jelly-bean,’ ‘a sissy,’ ‘a rookie,’ or ‘a woozy upstart’.
[US]Weseen Dict. Amer. Sl. 179: [College] Derail – A person disliked.

2. (US/N.Z.) denatured or adulterated alcohol, as drunk by alcoholics, tramps etc.

[US]G. Milburn ‘The Moocher’ in Hobo’s Hornbook 224: ‘Too bad,’ thought he, ‘that birds like him / Must stand out in the cold, / So full of derail hooch and all / The dingbat stuff that’s sold.
[US]Berrey & Van Den Bark Amer. Thes. Sl.
[US]N. Algren Walk on the Wild Side 101: They’re going to make out five or six phony orders [...] then go drink derail in Lafayette Square.
[Can](con. 1920s) O.D. Brooks Legs 99: The gnasher was now cursing, either from a nightmare or too much derail.

3. a person who becomes ill through drinking such liquor.

[US]E. Anderson Hungry Men 261: If I couldn’t whip a derail like him, I’d kiss anything you say.