Construct a sector plate
Dave Lowery explains how he harnessed the potential of this simple space-saving device.
Dave Lowery and Peter Marriott harness the potential of this simple space-saving device on their layouts.
Most of us try to cram as much as possible into our layout plans, and this is when space-saving solutions can come in handy. One of the simplest options is a sector plate. A sector plate is a pivoting section of track that allows trains to run from one line onto another without the need for points. Acting in a similar way to a turntable, many diverging routes can be laid to permit trains to access a fan of storage sidings or to re-emerge onto the scenic section on a parallel line. Sector plates can also act as one end of a run-round loop, allowing a locomotive to change tracks off-stage. They can be built to almost any length, to help shunt a locomotive alone, or entire trains. So useful is the idea that I built a whole layout around a sector plate. ‘Bevet’ is a compact ‘P4’ gauge layout, built in the mid-1980s and based on the London & North Western around the turn of the 20th century. In ‘front of house’ is the scenic layout, with station, goods yard and small engine shed. Two lines – the main running line and the route into the cattle dock – run under an overbridge and out of view. The sector plate is rotated to line up with either of these two lines while the train leaves the scenic section. The plate is then moved and the train reversed onto one of the hidden storage tracks behind the layout, or onto the adjacent scenic line during shunting operations. The process is simply reversed to allow
trains to move from storage onto the layout in the opposite direction. The sector plate is simply a length of plywood, about 2ft in length, secured to a pivoting point a few inches from the outer end by a standard wood screw. The screw is tightened only enough to keep the wood in place, while being loose enough to allow the sector plate to rotate on this axis. A means of aligning the tracks is essential for reliable operation. One simple solution is a small brass bolt and socket that will lock into place and hold the plate in position while the trains run back and forth.
As my layout is built to ‘P4’ standards, the tolerances of rails and wheels are finer, and the alignment, therefore, must be as accurate as possible. My solution was to place an etched brass W-iron unit from a wagon kit under the end of the sector plate, fitted with a set of brass bearings and a set of small wheels. Within the sector plate’s well are strategically placed pairs of phosphor-bronze strip, fixed securely to the wood base. As the sector plate moves, the wheels drop into the groove between the metal strips and align with the tracks above perfectly. Furthermore, to help smooth transition across the gap, the ends of the rails flare very slightly outwards on the sector plate and the running lines. As for the wiring, all you need to do is add a power feed to each rail on the sector plate. Only if the plate revolves more than 180º do you need to worry about polarity reversal, as you would with a turntable. Finally, a piece of black card is fixed to the side of the sector plate so that it blocks off the view through the bridge from the front aspect as the plate is moved. Thus, the happenings ‘off-stage’ are hidden from view. The principle is a simple one and the idea has been in use for many years. However, it’s still very effective and offers plenty of operational potential for spaceconscious modellers.
Sector plates can be made to almost any length. Smaller plates can handle locomotives only, replacing the need for points and a headshunt in a run-round loop.
The sector plate feeds the scenic layout by rotating between three storage sidings at the rear. Note how the control panel is fixed above the storage sidings to maximise space.
A set of brass W-irons and a set of wheels is secured to the bottom of the sector plate, supporting the track as the plate pivots on its fixed axis.