After a career at the head of the CMStP&P's main line passenger trains, the F-6 "Baltics" spent their last years in Chicago suburban service. This view furnished by Carl Weber, taken on June 28, 1953, shows No. 135 in that role just one year before its retirement. In addition to the modifications described for No. 128 previously, this engine has had its spoked drivers replaced by disc drivers of the Boxpok type. The F-6 class had a grate area of 80 square feet, an evaporative heating surface of 4205 square feet, and a superheater surface of 1815 square feet; the design included a combustion chamber and thermic siphons. For other dimensions see the page for No. 128. No. 135 was originally No. 6410, and was sent to the scrapyard in 1954.