The two locomotives shared as many common components as possible to allow easy conversion of the 8Bs to the 4-6-0 configuration - and both designs borrowed heavily from John G. Robinson's earlier GCR Class 8.

Following a high-speed incident that caused severe damage to its frame and cylinders, No.

1090 was rebuilt with 3 simple expansion cylinders in 1908, as a comparison to the GCR Classes 8D and 8E.

1090 was rebuilt, with the original 2 cylinders and Stephenson valve gear being refitted.

In 1925, several C4s were fitted with the LNER's trademark "Flowerpot" chimney, with one locomotive, No.

6085, also modified to fit the LNER composite gauge - a modification that the remainder of the class underwent between 1936 and 1939.

Two more members were withdrawn during World War II, these being Nos.