It was written by Banks, Jesse Rogg, Tim Anderson, Dacoury Natche, Aron Forbes and it was produced by the latter three.
Pitchfork Media said that "Trainwreck" evokes, to great effect, the particular darkness that was all over pop radio in the early '10s [...] blown−out vocals, big menacing synth pads, barely concealed panic.
[7] Shahzaib Hussain of Clash described the song as "a dizzying, trap−esque affair abiding more by pop conventions—intentional or not, it's a track that melds breakneck rhythm, vocal malleability and production value seamlessly, a template the LA artist should have utilised more of.
[6] Andrew Paschal of PopMatters said that "Banks crams rapid−fire syllables into verses, seeming to almost emulate the poetic style of Ani DiFranco or Joni Mitchell but lacking entirely the stripped down candidness of those artists, sounding more like a Meghan Trainor throwaway instead.
"[10] Writing for Rolling Stone, Maura Johnston expressed that "Trainwreck" combines rapid−fire lyrics about escaping a bad−news boyfriend, with hand claps, as if she's at the center of a supportive drum−machine circle, and the emancipation−minded.
[14] The music video ends with Banks' on top of one of the unknown men, she stomps on his head and it deflates, making a squeaky toy noise.
"[14] Gabriel Aikins from Substream Magazine described it as "darkly weird and memorable", while Kirsten Spruch from Baeble Music said that "although it's creepy as hell, Banks' artistic vision is very real and true".