The Hudson River Railroad, 150 miles in length, employs 225 "flag men," stationed at intervals along the whole length of the line. Just before a train is to pass, each one walks over his " teat," and looks to see that every track and tie, every tunnel, switch, rail, clamp and rivet is in good order and free from obstruction. If so, he takes his stand, with a white flag and waves it to the approaching train, as a signal to " come on "—and come on it does, at full speed. If there is anything wrong he waves a red flag, or at night a red lamp, and the engineer on seeing it promptly shuts off the steam, and sound the whistle to "put down the brakes." Every inch ot the road is carefully examined after the passage of each train.