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.

• 55455 Battery Box / IR Receiver, Train Baseplate 9V RC Train 6 x 30 [No Battery Cover] Sub-part of this part
• 55457 Battery Cover, Train Base 9V RC Sub-part of this part
• 2016b Control Unit / Remote, Train 9V / RC, Dark Bluish Gray Bottom, Yellow Buttons Pair of this part