Building the New Code Bricks
It's possible to build one of the unpublished code bricks in two ways. The first attempt involved taking a red Stop brick and cutting one of the bars down to the right length. Unfortunately this method did not allow for easy experimentation. Instead these code bricks where built by adding a wooden bar to the Reverse code brick. Using hot melt glue, it is easy to tack the short brick temporarily in place while refraining from doing any permanent damage to the code brick. Later, the short bar can be glued more permanently into position.

The bars can be easily crafted by cutting them out of lengths of a popsicle stick. Although having a sloped face to the bar is important, it's more important to get the length of the top of the bar cut to exactly the right length. Once the bar is tacked in place, it's necessary to test the new code brick by running the train across it from both directions. Slight variations in bar placement can cause the Intelli-Train engine to behave differently as it approaches from either side of the bar.

Disassembling the Intelli-Train Engine
Here is how an Intelli-Train engine can be dismantled, but please don't blame me if you break yours in the process. There are several small and delicate parts inside, and it's quite easy to break them without meaning to.

1. Remove the windscreen by snapping it off of the top of the train.
2. Unscrew the two captive screws, then remove the battery bay door.
3. Take out the batteries and remove the four screws underneath. Also remove the screw at the front of the engine.
4. Partially crack open the engine from front to back, along the join between the black and the yellow plastic.
5. At the back end, the two parts will remain connected by the two tabs. Insert a thin flat blade screwdriver at the back edge of the bottom of each of the tabs. Pry the tabs with the screwdriver to release the catches on the housing.
   
6. Split apart the halves being careful not to damage any of the components inside. The wire sensors are particularly fragile.
7. When removing the innards from the black bottom housing, two of the the battery contacts will need to stay connected to the circuit board so they need to be carefully slipped out of their slots in the battery bay.

Inside the Intelli-Train Engine
The inside of the Intelli-Train reveals some interesting bits about the engine. Pictured below is the gear box and the electric drive engine just visible above the upper gear.

The unpublished shop code brick, activates a new gauged consumable on the train. Both refilling buttons work for adding either gas or oil to the engine, but inside the engine they are labelled "TOOL" and "FUEL." This is further evidence that the unpublished brick was related to a mechanics shop set.

The infrared receiver on the Intelli-Train engine remains a bit of a mystery. It is located at the top of the engine back between the two refilling buttons. There does not appear to be the usual black infrared window for the detector to see out of. Either the buttons are acting as a light pipe to bring the infrared signal to the detector, or the yellow train body itself is translucent to infrared light.

There is a sensor rig on the front axle that counts the distance that the train travels. Brushes ride on the metal axle and twice pre revolution the electrical connection is broken by a plastic bar on the axle. The Intelli-Train engine uses this method to determine how far it has traveled rather than relying on a timer or by measuring the distance using the electric engine or gear box.

Questions Still Remaining
There are still a few things that need to be researched to about the Intelli-Train:

• What smart-car is supposed to interact with the unpublished Wash brick? What is it's pin layout?
• Is it possible to decode the infrared communication between the Intelli-Train engine and the smart-car
• What colours were the unpublished code bricks?
• Is it possible to hack the Intelli-Train engine to add headlight LED's and a tilt shutoff switch?

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Intelli-Train LEGO Duplo Train Track Layouts