A challenge that was always there from the start and which had been exercising my mind from the day I started planning this model railway was how I was going to cope with taking an overhead-electrified model railway line through tunnels. The overhead on this layout is realistic in appearance but is non-functional, the trains picking up their current through the normal two-rail system just as models of diesel or steam trains would do, but it is just as important that the pantographs keep contact with the wire or else they would cause major problems, possibly including damage, if they are dewired and snag the catenary.
The solution I adopted, and which I have since heard has been done by others, was to glue a length of rail to the roof of the tunnel, soldering the contact wire carefully at each end to make a smooth transition. A pantograph then glides from wire to rail as it enters the tunnel and back to wire when leaving the tunnel, but to the observer the wire simply seems to enter the tunnel as it would in real life. Because of the presence of overhead lines it is impossible for a viewer to get their eyes low enough to look into the tunnel and see that I have thus cheated! See it done on the latest video:
The next project will be to take the wire to the next tunnel mouth which will be the entrance to the hidden sidings where I shall have to make arrangements for the overhead to end in such a way that raised pantographs are wired as they leave the hidden area for the visible part of the layout. Once that is done I can begin the gradients and spirals, with more complex tunnels, which will take the other track up and over the mountains to the terminus to be constructed above the hidden sidings. In many ways the short section of track on this first line has been the test-bed for the complex sections to come, but in any case it had to be built first because the rest will be built over it!