These were display layouts so spurs were setup to demonstrate operating cars and accessories. The cars weren't ment to be moved so the "dummy" mainline/double tracks were used for scenic interest (like to show the 450 signal bridge). Also, a lot of times the spurs that were connected to main tracks werent powered directly. The D-131 posted above used a manual switch and there was a insulated pin in the center rail preventing a direct movement into the spur. Some modifications to the plan are necessary for making these more operator-friendly.
Also, one note on the D-27 Fastrack plan. The down grade is very steep and i recall from the CTT article that the track on the start of the grade had to be physically bent downward to have a smooth transition. Care would have to be taken that a smooth transition can be made because you can't bend Fastrack like that. Use of transition tracks and a piece of tubular may be necessary in that location.
Peter
Thanks Peter, interesting points there. I don't completely understand which layouts were made only for dealer displays and which were specifically for retail sale. The Lionel layouts typically allow unattended operation of two or more trains, and accessories for operating cars. It's curious that they made some tracks dead-ending in tunnels for scenic effect rather than for train operation.
The D-27 layout has a downgrade of about 6% and short upgrade of 10%, apparently intended for operation in one direction. I saw an instruction sheet online (not very clear) which appears to maybe have different voltages applied to different sections of the track for speed management. The downgrade section helps push a longer train through the steep upgrade, possibly a good trick to use on other layouts.
