### Clue: Travels with old woman in express one to hold up train? (10)
### Answer: BRIDESMAID 
 ### Explanation: Definition: one to hold up train
 [ RIDES(journeys on, say, a horse/travels) **plus**(with) MA(an informal term for one's mother or an old woman) ] **contained in**(in) BID(to say/to express, say, a greeting, as in "to bid welcome").
Defn: …, the train of a bride's wedding gown, that is.