Instructions for Crossover

Click here for a 28K JPEG.

Inspiration for this project came when somebody (who shall remain nameless but I still married her later) dropped a steam iron on a train layout that was set up in my living room. It made a nasty dent in one of the straights and I thought I was going to be left with an annoying odd number of tracks in my collection. After fiddling with it for a while I discovered that the dent was exactly where a gap would have to be cut if it was made into a crossover. Cool, I thought, and decided to sacrifice another straight to build a crossover.

The crossover allows two tracks to cross each other at right angles and electrically isolates one direction from the other. This allows two independent circuits to cross over each other. Continuity over the crossover is maintained by wiring attached to the rails.

I built one of these about three years ago and it has worked perfectly ever since, it has never caused a derailment or had a train get stuck on it.

To build this project requires no LEGOŽ building skills at all but you do need to be fairly adept with a soldering iron and a hacksaw.

You will need:

For the wire I used thin grey plastic coated speaker wire, grey so that it doesn't show up against the track. I found some very good epoxy resin glue at Radio Shack that says it is for plastic (i.e. mending smashed up radio controller cars) it sticks remarkably well to LEGOŽ. I'm not sure how well ordinary epoxy works in comparison.

Okay, here's the step by step instructions:

Step 1


Take one of the straights, this will be the main straight. Remove a 4x4 section of sleeper from the very centre of the track using a straight edge and sharp knife. The gap should be exactly the width of a sleeper.

Step 2


Using the hacksaw, carefully cut four gaps in the rails as shown. The figure shows a side view close-up of the left cut, the right cut is an exact mirror image. The outer cuts should line up exactly with the existing holes in the plastic, the inner cuts should be such that the gap is 1/8 inch. File the edges to remove any burrs. Use the pliers to make sure the metal is still tightly crimped over the plastic.

Step 3


Take the second straight and cut in the 4 places indicated, A, B, C and D. The A and D cuts are made flush with the sleeper, the B and C cuts are made so the centre section is 1 9/32" long (i.e. 4 studs).

Step 4


Using the knife, remove the 8 sections of the sleepers as shown. The pieces should all now fit snugly with the main piece.

Hint. Cut off the two 1x2 plates from the middle piece first. Then you can clip them to the other pieces to use them as a guide to cut out the 1x2 holes.

Step 5


Glue all the pieces together using the epoxy resin glue. I was fairly liberal with the glue on the underside where it won't be seen.

Hint. Make up a LEGOŽ frame to keep the track straight as the glue dries. Be careful not to glue the frame to the track!

Step 6


Now cut and strip the wires for the main track, shown here in red but I used grey wire so that they don't show up too much. Solder to the outside of the metal rails where indicated in light blue. Try not to hold the soldering iron on too long otherwise the plastic will melt.

Step 7


The wires for the other direction are mounted underneath. You will need to make small notches in the plastic webbing so that wire sits inside the hollow under the rails. Strip the ends of the wire and thread them up through the gaps that you should find there, thoughtfully provided by LEGOŽ! Solder to the outside of the rails as indicated in light blue.

That's it! See the figure of eight layout for an example of it in use.
Click here for a 30K JPEG of a Metroliner in a close call with a hopper wagon.

Footnote

Since writing these instructions I have made a few more crossovers, and have come up with a few more tips.
  • I have acquired a Dremel MultiPro Tool which is much better at cutting through the rails than a hacksaw, it leaves a clean cut and doesn't loosen the metal. It can also be used to round off the edges a bit so that train wheels don't catch on the cross rails.
  • I switched to thinner, solid core wire for making the electrical connections. The solid core is easier to solder than multistrand, and the thinner gauge allows all the wires to be run underneath.
  • I drilled holes in the platic webbing underneath instead of making notches. It's a bit fiddly to run the wire through them but means the wires don't have to be glued in.
  • When it's finished, make sure that the train motor wheels can't touch the crossrails when they pass over, otherwise they will momentarily short out. If they can touch, grind them back a bit until they can't. The Dremel is ideal for this.