It is a long narrative poem in blank verse about the construction of the first transcontinental railroad line in Canada, that of the Canadian Pacific Railway (CPR), from 1871 through 1885.

The poem won Pratt the Governor General's Award, Canada's top literary honor, for poetry in 1952.

The poem also has a political context, illuminated by the debates between Prime Minister John A. Macdonald (for the railway) versus Edward Blake (against).

The physical tests throughout the poem are a battle between the forces of nature (the Canadian Shield is personified as a prehistoric monster) versus the combined might of the construction team headed by William Van Horne.

Scott, critiqued Pratt for overlooking the thousands of indentured Chinese labourers who actually built the railway in his poem "All the Spikes but the Last.