My original idea for a crossover track was to have a connecting track that curved out of one track and into another, but it took me a while to figure out how to make one, so I built the straight crossover track first. After I built that piece of track, I started putting a plan together for making the curved crossover. What I needed was a pattern that I could follow with the router to make the curved cuts.
Playing with some of the existing track, I found a combination that looked right. Again I used 6″ straight tracks as the base, but this time I used two small curves overlayed on top of the straight pieces as an offset bend. The distance between the tracks turns out to be much greater than in the straight track, so unfortunately this piece wouldn’t mate with the other crossover, but I could live with that.
I used the two curved pieces to make the template for the router to follow. Even though I technically needed one side of the curve to guide the routers. I cleaned up both sides and made some spacers out of dowels that were the same diameter as the guide bushing I was going to use. I also drilled a 1/4″ hole in the end of the spacers and inserted a 1/4″ dowel into the hole. This 1/4″ peg would fit in the existing track to help align the template. Once the template was aligned I just pinned down both sides of the template with my pin nailer.
The first time I used the template I screwed up. I wasn’t thinking about the difference between the radius of the curves on one side of the offset track and the opposite side. It’s rather hard to explain so I included the three following pictures to explain the problem better than my words ever would.
I labeled the sides of the template so I wouldn’t get confused, the side labeled outside always goes on the outside track and the side labled inside always goes on the inside track. In this picture the template is set up to cut the first crossover. Notice how the curve of the template follows the curve of the groove.
In this picture you can see how the curve of the template doesn’t match the pre-existing groove — the labels don’t match the postion. This is the mistake I made the first time.
Finally this picture I’ve left the track in the same position to emphasize the correct way to position the template to cut the opposing track. Notice how the labels are once again in the correct position. To cut the crossing track, just flip the jig over and repeat.
In retrospect, the curved crossover didn’t work as well as I expected. Even though the trains don’t have to make sharp turns like on the straight crossover, the multiple changes in direction make it harder for them to stay in the grooves. After much play, my son and I have found the straight crossover actually works much better for switching tracks.