I bought my daughter Cargo Train 10875 and it all works OK with one exception—the blue action brick has no effect. The other action bricks all have some noticeable effect.

I asked LEGO to send me a replacement blue action brick, and they did, but the new brick doesn't have any effect either.

Has anyone else had this problem? I'm wondering if the train itself is defective.

  • 2
    Does this answer your question? How do the DUPLO Action Bricks work? Jan 23 at 20:09
  • 2
    Try cleaning the light sensor on the bottom of the locomotive. Jan 23 at 20:09
  • 1
    Well, if sensor cleaning does not change behaviour for blue colored action brick I would suggest getting in touch with LEGO Customer Service again asking for locomotive base replacement. It might be that the unit itself has some issues.
    – Alex
    Jan 27 at 10:58
  • 1
    I cleaned the light sensor on the bottom of the locomotive, but it made no difference. I will contact LEGO about replacing the locomotive.
    – Adam Ralph
    Jan 28 at 13:30

1 Answer 1


It turns out the locomotive unit itself must have been faulty. I returned the entire set for a full refund and ordered a new one, and the locomotive from the new set performs the expected action when it passes over the blue brick.

I’m glad I went to the effort because the action triggered by the blue brick is probably the most interesting of all of them.

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