>>1744346It works because a two wheeled bogie has a short wheelbase, and the centre bogie has a lot of side play. In fact B-B-B locomotives can negotiate tighter curves than C-C locomotives.
Lots of other locomotives, especially in Russia, Italy and Japan follow the same design plan. When there are a lot of sharp curves too tight for three-wheeled bogies, a need for more power than 4 axles can without slipping, or providing stability at higher speeds.
Pic related is a US example, the EMD GM10B
