Set-Size vs Full-Size
Set-Size engines and cars (the ones included in most starter sets) are shorter. Typically around 10" to 12" long.
Example: The 40650 caboose on the right is 12" long and is a Set-Size car.
Full-Size engines and cars are purchased separately. These engines and cars are typically from 18" to 24" long, almost twice as long.
Example: The 43790 caboose on the right is 20" long and is a Full-Size car.
While all LGB engines and cars run on the same track, use the same couplings, and the same power supply, the size difference between Set-Size cars and Full-Size cars makes them visually incompatible.
Please be careful when purchasing additional cars for your starter set. Pay attention to the car length and choose cars that are 10" to 12" long. For example, all ToyTrain style cars and most Christmas cars are the smaller Set-Size.