The introduction of fixed wheel container wagons coded _KQ_ presented an access problem. Containers on the wagons could not be accessed for manual loading.
When containers were loaded onto bogie flat wagons, the container doors were facing into the wagon centre with gap between containers. This allowed for manual access.
To overcome the access problems, twenty wagons were modified in 1969. They were rebuilt with sheet metal decks. The code adopted was KL, the 'L' to indicate 'Loading'. The wagon numbers were 1 - 20. The wagons were converted from long wheelbase _I__ and _IA_ underframes.
By 1975 the majority of the wagons were in storage.
The KL wagons were removed from traffic and scrapped from the late 1970s to the mid 1980s.