running on monorails (overhead railway systems B61B)

Full Title

Trolleys or crabs, e.g. operating above runways (runways, tracks or trackways therefor B66C7/00; winch mechanisms B66D) > with operating gear or operator's cabin suspended, or laterally offset, from runway or track > Underhung trolleys (power-operated hoists with driving motor and drum or barrel contained in a common housing B66D3/20) > running on monorails (overhead railway systems B61B)