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~2006
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A photo of the M>ltc layout at Brickvention 2006.
My bridge is in the foreground. Also note part of a stone road bridge on the far right, and the trestle bridge behind.
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This is a bridge I built for the M>ltc train layout in 2006. It is loosely based on the Batman Bridge near Launceston, Tasmania. The main pylon actually turned out to be reasonably complex - I wanted something strong (to be able to support the bridge deck), as well as look good. I ended up constucting it with an inner Technic core, surrounded by bricks. The trickiest part was the peak - coming up with a method to get such a sharp angle to look good was surprisingly difficult, but in the end, the simple solution was the best!
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| The pylon is constructed with a Technic core, made up of side-by-side beams connected with pins, plates, and tiles. It is surrounded with brick cladding, 1 stud thick. |
At regular intervals down the pylon, 1x1 Technic bricks are attached to the core with a pin, and fit into holes in the cladding. Even though the positions were calculated to match exactly, it turned out that LEGO tolerances aren't exact (who knew????), which resulted in the core being under slight tension. This was actually a serendipitous result, as it meant the pylon was effectively "pre-stressed".
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The peak angle took a while to figure out. I tried lots of different techniques, but this was the one that worked the best. Note that the 2 sides of the pylon are only held together by 2 sets of hinge plates at the top.
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Here you can see how I continued the Technic core up inside the peak, in order to strengthen it. Without this, the peak would break off very easily.
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Just thought I'd demonstrate how strong it ended up. Here I am holding it at the centre - I could actually shake it up & down like this and it would flex but not fail, due to the "pre-stressed" core.
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Having a strong pylon was a good start, but in order to be able to support itself, it had to have a very strong anchor point for the cables. I would have preferred a solution that didn't require mutilating LEGO parts, but I just couldn't find one - it is just too heavy. So in the end I opted for mutilating the least possible parts, and the solution I came up with called for only 1 modified part.
As our layout is set up on 96x96 stud chipboard, I decided to use that to provide the solid anchor point. That meant I had to either build my module without baseplates, or drill through them. As I just didn't have enough bricks for the former, I chose the latter. The position of the bridge and anchors was fairly restricted because of the track layout, and the anchors had to be wider apart than a single baseplate. But rather than drilling 2 baseplates I decided to cut 1 in half and have 1 anchor point on each half. So here's how it went:
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| The anchor points were built, and holes drilled in the baseplate halves to tie them to the chipboard. Then matching holes were drilled in the chipboard. |
The anchor points were tied down through the baseplate halves, and other baseplates added to fill the gaps.
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Covers were made for the anchor points, so they look nice.
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The cladding added, the riser is required to get up & over the pylon base, and some slopes to hide the edges once it's up.
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Once complete, erecting the bridge is simplicity itself:
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Step 1 - Raise the pylon and tie it to the anchor points.
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Step 2 - Add a deck section and attach the cables. |
Step 3 - Repeat Step 2.
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Step 4 - Repeat Step 3. |
Step 5 - Add the last section. Note that it doesn't require cables as it will normally be attached to solid ground on the other side. |
And there you have it.
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