After some time both McDowell's obtained employment with the Public Works Department (PWD) at Kawatiri, initially helping to construct the railway tunnel there. McDowell the senior eventually retired to Glenhope, but Karl worked on construction of the Nelson Railway for the remainder of 1920's until construction was halted just short of the Owen River at Christmas 1929 due to the worsening economic effects of the Great Depression.
While with the PWD he became close friends with his brother in law Ernie Heslop, and together they made numerous fossicking trips to the Howard throughout the 1920's, often working on claims together at different times.
After the suspension of the railway construction Karl was fortunate enough to be kept on with the PWD and was involved in carting stores back from the various camps to the railhead at Glenhope for dispersal. When that job was completed sometime in 1930 he travelled north to Wanganui, and worked there for several years before returning to the Nelson District during the mid 1930's.
Karl returned to the Howard and entered into a partnership with Ernie Heslop. Despite the failure of Ernie's marriage to Karl's sister the partnership endured, and the two friends continued to work together for many years. With the coming of the 1940's, and easing of the Depression, people were beginning to leave the Howard, and during this time Karl and Ernie acquired several other claims, working these and their own until Ernie died of a heart attack about 1950.
For a time Karl entered into a partnership with another man Dave (Sam) Zimmerman, however Karl was now aged in his 50's and married with a young daughter (my mother), so eventually in 1954 the family decided to leave the Howard and move down to Westport, thus ending a 40 year association with the former.