I'm fairly sure these are correct but would appreciate help with the parsing......
17a. Lifts and wear and tear used to go west internally (5,2) - RIDES UP (Lifts)
24a. Ages visibly: no train back, alas, ultimately (5) - YONKS (Ages)
38d. Composer of note well received by a large British assembly (5,4) - ALBAN BERG (Composer) - Other than A L(arge) B(ritish), I can't see it.