Throughout the 1920s the Canadian National did add to its prairie branch line network. In 1929 the CNR and the CPR both sought approval for building significant extensions in Saskatchewan and northeastern Alberta. Sir Henry Thornton, Chairman and President of the CNR, stated that the CNR did not wish to be excluded from territory it had already colonized and into which it planned to extend.4 Sir Edward Beatty, Chairman and President of the CPR, defended the CPR plans to extend into the northern prairies. The CPR had colonization lands there. Settlers were petitioning for rail lines. The CPR was also interested in accessing mineral deposits in northern Saskatchewan and in connecting with the NAR from Saskatchewan along a line planned to run south of Cold Lake.
The federal government approved extensions for both railways. The CPR built through CNR territory with its Edmonton-Lloydminster line and with the extension of several branch lines in northwestern Saskatchewan. As suggested by Sir Henry Thornton the CPR did negotiate running rights over CNR lines to access some of its new branch lines in northwestern Saskatchewan. In Alberta both the CPR and the CNR negotiated running rights over sections of one another’s lines. With the construction of the joint track between Rosedale and the Trefoil both railways gained access to the coal reserves east of Drumheller. The Trefoil-Rosemary section of this line built by the CPR serviced land in the CPR’s central and east irrigation districts.
As economic depression and drought persisted into the 1930s, proposed branchline links were abandoned even after significant grading work had been completed. In east central Alberta the CNR did lay track down on its Hemaruka-Scapa link. This section was never completed to optimum operating standards.5 Finally by 1933 the Alberta railway network reached its peak as branch line construction came to a complete halt.