### Clue: Boy cycles to end of platform to help Southern train attendants (11)
### Answer: BRIDESMAIDS 
 ### Explanation: Definition: train attendants
 B(in Internet slang/texting, "boy"/brother/bro, as an address for a friend or associate) RIDES(… on a bicycle, say) **plus**(to) **last letter of**(end of) "platform" + AID(to help/assist) + S(abbrev. for "Southern").
Defn: …, the train/piece of material trailing a wedding dress, that is.