Since the advent of Peco's Code 75 track being introduced, one common question which often arises is that of how to join Code 75 track to Code 100 track.
Peco provide a solution in the form of some special conversion fishplates but these look absolutely awful, they are way over scale and they are really not acceptable for use in the scenic part of a layout.
The following is a simple way of joining Code 75 and Code 100 track which gives a very neat result which is perfectly usable in the scenic part of a layout.
We start by filing the underside of the code 100 rail such that the web is removed and the rail is the same height as the code 75 rail. The following photos show code 100 on the left and code 75 on the right:
We then use code 75 fishplates to join the two pieces of track together and close up the sleepers. Code 100 is now on the right:
Side-on view showing code 75 fishplates which have now been soldered to the code 100 rail. This is done by tinning the underside of the code 100 rail, fitting the fishplate and then heating again to melt the solder inside the fishplate:
Another view of the finished product. As can be seen, this is a vast improvement over the Peco offering and if done neatly, it is actually difficult to notice the difference, especially when ballast is laid around the sleepers.
Note how the chairs have been cut off of the sleepers to create a recess for the fishplates on both code 75 and 100 sides. This enables the sleepers to be placed under the join without causing a 'hump':
When laying the track, it is necessary to place some very thin card under the code 75 sleepers because they are slightly lower in height than code 100. Once ballast is laid, this does not show.
It is important to ensure that the tops of the rails over the joint are level. If they are not, you can reheat the solder in the fishplate to adjust or it may indicate that more filing on the code 100 rail is necessary.