Yesterday I blogged about building a car transporter set that I bought with the intention of turning this rather dull blue wagon into something more interesting.

The first thing to do was take off all the bits above the base plate. The little Octan tank will come in useful somewhere.

This left a nice bare surface to start building on. For reference, this plate is 28 studs long and 6 wide. The holes in the middle are because it is also used in the model locomotive and the wires need to go through somewhere.

Just to give a sense of the below decks engineering, here's a picture of the wagon's wheelsets. You can see how it has two free-turning bogies to enable it to cope with the sharp radii of the Lego track system.

Relocating the transporter deck to the wagon was tricky. For starters, it meant moving the connectors out a bit as the red bases with holes for technic pins had to overhang the side of the wagon. (Hey, in the background are the cow and scrap wagons!)

When completed this meant the transporter deck was 10 studs wide, when measured from the outer edges of the support beam mountings. The wagon base was only 6 studs wide. That's two thirds wider in real terms and would make the clearance pretty huge on corners.

This felt even more obvious when the decks were collapsed for loading, but at least they lay flat (well, flattish).

One plus was there was plenty of space up top for both cars. In fact, too much space, as the top deck was 32 studs long.You can also see in this view just how wide the whole mechanism was.

The overhang on the top deck was a real problem. For one thing it looked a bit weird. For another if I ever built another of these things they couldn't be coupled together without clashing as the overhang went beyond the buffer heads. I know it's only Lego, but it just wouldn't be built like this.

You can see the overhang in this photo, and also the instability on the lower deck caused by having to mask the base units for the upper deck supports.

So, in conclusion, it was a workable model but it didn't look right and it didn't work very well. I wasn't happy with it. Somehow I was going to have to find a way to lose 4 studs from the top deck and move the supports in to the true edges of the wagon. An 8 stud wide car transporter would still be ungainly, but it would work.

The great thing about Lego is you can just take it apart and put it back together again if it's not looking right. In my next blog post I will tell you all about that.