switch (FEAT_TRAINS,SELF, switch_hopper_wagon_layers, [
STORE_TEMP((getbits(extra_callback_info1, 8, 8) < 4 ? CB_FLAG_MORE_SPRITES : 0) + PALETTE_USE_DEFAULT, 0x100),
getbits(extra_callback_info1, 8, 8)
]){
0: spriteset_wagon_wheel;
1: spriteset_hopper_wagon_back;
2: spriteset_hopper_wagon_cargo;
3: spriteset_hopper_wagon_front;
return spriteset_hopper_wagon_back;
}