The first run of China built Con Cor Hudson’s had engineering plastic driver centers. Not a good idea because they interlocked with the engineering plastic gears, or rather didn’t....to keep the drivers in gauge. This caused a failure in the loco before the stripped electrical wire insulation instead of rubber tubing for the universal slipped.
I believe second run (fancy paint schemes and shrouded versions) had these deficiencies corrected. Apart from the useless flywheel the “new’ version had increased diameter drivers, tender wires through the trailing track drawbar, headlight and backup tender lights.
Still the best, most foolproof design steam engine in any scale!!
Charlie Vlk