the.com/handcar

means A small open railroad car propelled by people pumping a hand-operated lever, once used by track crews to inspect and maintain the rails.

from A transparent American compound from the railroad age: simply "hand" plus "car," naming the thing by how it moves — by hand, not by steam. It dates to the 19th-century spread of railways, when crews needed a light, muscle-powered way to roll along the tracks. Also called a "pump car" or, informally, a "velocipede," for the same up-and-down labor.