GR translation: chrome-sprung prams of black hide

[Mike Jing]

V132.3-7, 134.15-20   In the stations of the city the prisoners are back
from Indo-China, wandering their poor visible bones, light as dreamers or
men on the moon, among chrome-sprung prams of black hide resonant as
drumheads, blonde wood high-chairs pink and blue with scraped and
mush-spattered floral decals, . . .

What does "chrome-sprung" mean?