Lionel Bathtub Gondolas All Lionel Bathtub Gondolas feature the revolutionary rotary coupler which allows the cars to perform in O gauge the same way that they do in real life. When used with the Lionel Rotary Coal Tipple (offered in Lionel Classic Trains Volume I 2002), an entire coal train can be unloaded without uncoupling the cars (Coal Tipple Coal Pack required, see page 117). Two new road names are available in 2003, Norfolk Southern and Union Pacific. A new Burlington Northern Coal Train set is also available, see page 16. Each 3-Pack features one dual rotary coupler car and two single rotary coupler cars. The add-on cars all feature a single rotary coupler.