Tom the switchman has to work though his boy is dying at home. In his grief he falls asleep at the switch. A disaster is barely averted when daughter Nell, bringing good news, throws the switch. Tom is found dead of grief, but Nell is rewarded
Cohen notes that (at least) two other poems were written with the title "Asleep at the Switch" before Shackford published his piece in 1897. The earliest was by George Hoey, and that poem appears to have been the most popular in the wider world; it is the only one of the three cited in _Granger's Index to Poetry_. - RBW