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LEGO City Cargo Train 7939 Review



This is a review about the Lego 7939, also known as the Lego Cargo Train build. It belongs to Lego’s popular City theme, and contains a total of four minifigures. There are also 839 pieces in total, according to the official Amazon Website. It was first released in 2010. During its initial launch, the 7939 was priced at around $158.20.


After Lego decided to discontinue the electric track period series more than a decade ago, they were immediately replaced by brand new IR trains on a plastic railway, released soon afterwards in 2006. In 2009, Lego treated its audience to the Power Functions Emerald Knight set.


The Lego 7939, during its release in 2010, gave Lego fans enough time to prepare for yet another train set – And this time, it combined the PF functions of the EN, along with a cheaper battery box and a brand new motor function. The 7939 includes two train sets that were new during that time – The Passenger Train build, and the Cargo Train. Accompanying them was a train station build, also relatively new during that period (the Lego 7937). The last build consists of a small level crossing, with a passenger bridge.


The front side of the box does not really feature anything, as it’s a build that isn’t associated with a particular blockbuster franchise, such as Star Wars or Batman.


The back side of the box. Since it doesn’t contain a detail shot (compared to the Lego boxes released this year), it only tells you that the set includes its own eight-channel IR remote in the build.


The instruction manual begins with a page that informs you how to place the batteries right in the socket. You might have to rush to your nearest hardware store and purchase six AAA-size batteries. All six of them are required for the build to completely function. Three more AAA batteries are needed for the remote control to work. Another link will tell you how to troubleshoot the official Lego Website on the Internet, or in case the build malfunctions.


One of the great things we liked about this vintage build is that the TLC didn’t even include a piece callout. This isn’t something to be worried about though, since it’s not that big of an issue – For children who want to finish this build, you can completely ignore this problem since the instructions found inside the booklet are easy to follow anyway. Most builds deal with a couple of bricks that you can add to one step at a time.

The thirtieth step involves the 1 x 2 brick being added to the grill.


Step 31 deals with the curved sloped brick in the build, while step 32 features the 1 x 2 plate with a handle going on one side. One brick always equals to one step when it came to this build – Builds from 2010 didn’t require too many piles.

The Lego 7939 is accompanied with six instructional booklets, and the largest one deals with building the locomotive. People who have finished this build loved the fact that it made for a good bonding session with their friends or family.


The box contains eight packs for the building parts, eight straightened tracks for the locomotive to go through, sixteen curved tracks, sixteen flexible tracks, eight types of magnetic couplings, two points, two types of train bases, one IR remote control, one IR receiver, a battery box, a motor, and a sticker sheet.


Previous owners have felt slightly overwhelmed by the amount of pieces that this build contains – But after 2010, the amount of bricks found in these expensive Lego builds just kept increasing in size. A new battery box has also been included in the build.


If we take a closer look at the battery box, we will notice that it’s got the same look and shape as the rechargeable ones from the previously-released Emerald Night build. This is actually great since it’s got a broader, rectangular shape and is much smaller than its previous incarnation. The battery pack measures 4 x 8 x 4. It fits so much nicer inside most locomotive builds, rather than older train or locomotive builds. It’s also smaller than the previous build-in baseplates found in other builds such as the Lego 7898 – We could probably give credit to the build’s six AAA batteries. Everything works well – We can’t say the same thing about the total run-time of the train, though.

We have compared all of the battery boxes that Lego has released so far, and we think the ones that accompany the 7939 are the best ones so far. What was really great about the 7939 is the fact that you can fill its brand new battery box with old versions of battery boxes or rechargeable batteries too.

Its brand new motor came with a build-in cable connection.


The eight-channel IR RC has the ability to only control one train – So the steering is slightly oversized. The only required functions here are one steering wheel, alongside the stop button. Driving a larger layout here is much more different compared to the rest, so it was nice to see that TLC managed to implement a couple of spare functions in the 7939.

One of the few disadvantages here is that the train doesn’t have its own set of lights. We’re not really sure if this is due to the limited power supply that comes with the new battery box.

Contents of the first bag include lovely tiles measuring 2 x 4, a brand new 2 x 2 modified facet bricks in yellow shades, as well as a new train front base-brick.


We like the fact that Lego used to hand out brand new and wanted bricks like before – A good example of this is the new yellow plate. However, when it came to the locomotive’s built, another brick took over its place. Both tiles have been covered up by a plate measuring 4 x 10. Plates measuring 2 x 4 are also being used here, in gray and blue hues.

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