Variants of a mold are catalogued separately, so each one has its own sets and minifigs. Check these too if something you expect is missing here.

• upn0259c01 Motor, Train, 4.5V 12 x 4 x 3 1/3 Type II this part is a sub-part of it
• upn0274c01 Motor, Train, 12V 12 x 4 x 3 1/3 Type II with Three Side Holes this part is a sub-part of it