No. 1021 "Queen Mary" after the rebuild
Locomotive Magazine, May 1916
One of Robinson's first developments was the class 11B, which was intended to meet the increased demands of new lines. They were similar to the class 9J “Pom-Poms” freight locomotives and were therefore also called “Pom-Pom Bogies”. On some lines they could reach an average of 60 mph (97 km/h). In terms of power, they were soon outperformed by Robinson's newer designs and rebuilt. Only two locomotives received a new saturated boiler and became class 11C. Between 1909 and 1927, all other locomotives were rebuilt with a different boiler, which was delivered directly with a superheater from 1913. The last ones were able to remain in service until 1950. 