A Surface-mounted Sector Plate

By John Rodway from Gazette Vol 20 No.8 August 2018


The tall industrial buildings that form the backdrop on Gillan and Brown provide an excellent location for the sector plate subterfuge that adds to the operation of the layout

Sector plates can be useful where off-stage space is tight. On Romiley Methodist Railway Modellers Gillan & Brown industrial layout (Gazette: August 2008, Layouts to Inspire, 2016) there are two. One carries whole trains and gives them access to the back-stage storage sidings / fiddle tracks. The other is within a building and allows single wagons to be transferred to and from a track hidden behind a factory. Here incoming loads can be conveniently removed or outgoing loads added, unseen by the audience. The two sector plates use different designs to match their contrasting sizes and function.

The longer sector-plate is conventional, in that it is a plank of 9mm ply that moves within a pit in the baseboard surface. Such recesses take time to cut accurately and they permanently commit that baseboard to their initial position. By contrast, the smaller sector-plate is surfacemounted, requiring just two holes in the baseboard, one for the pivot and the other for the electrical supply. Should changes be required, nothing irreparable has been done to the baseboard.
This smaller sector-plate is based on two lengths of flat-bottomed rail soldered to copper clad paxolin sleepers in the usual way. It simply slides over the baseboard. At the pivot end there is a more substantial rectangle of cooper-clad paxolin, held to the baseboard with a bolt, washers and nuts. As with the sleepers, the copper is thoroughly gapped to prevent electrical shortcircuits. Though this track is inherently rigid, repeated movement would stress the limited joint areas between the sleepers and rails, especially when carrying a loaded wagon, so two substantial angle brass longitudinals were sweated to the extremities of the sleepers and to the pivot plate.

This view from the operators’ side clearly shows the brass handle used to change the alignment of the plate and also the gap in the buffer block to accommodate auto couplings on stock. A wagon arriving on the sector plate can be moved, by hand, onto the track inside the building, bottom left, to have a load removed or added before returning to public view. The recess into which the removable building fits is also clearly visible.

Also attached to the pivot plate is a buffer stop. Since this is concealed from public view, it is just a block of metal soldered to the ends of the longitudinals and the pivot plate. However, there is a central gap to accommodate the loop of Winterley couplings, and a horizontal hole on the operators' side into which fits an L-shaped rod. This rod is held in place by a clamp nut, a former gas fitting, and forms a handle to move the sectorplate. The handle projects through a horizontal slot in a modesty screen that clips onto the rear of the baseboard.
To further enhance the illusion, the spaces between the rails and the longitudinals are filled with thin ply, painted with the same palette of mottled colours as the floor of the building and the concrete pad outside, though grading to darker colours close to the buffer-stop.

This screen partly shades the interior of the building, making it difficult for the public to see what is happening within the building. It also prevents the public from the embarrassment of catching a glimpse of the operators' tummies -not always a pretty sight. To further distract the public, their side of the screen is painted with indistinct blocks and stripes of greys, browns and whites, giving the impression of the interior of a large engineering workshop. The screen still allows operators to move wagons from above by fingerpower. For storage, the handle and screen are removed.

Viewed from the front of the layout with the building removed, this shows the sector plate aligned to the incoming track. The operators’ handle projects through the rear wall of the building.

The ‘roller’ door to the building is only raised when wagons are to pass through. They partly block the view of the interior from the viewer’s side. As a further distraction, there is a twoaspect electric light signal on the wall outside the doorway. By the use of a micro-switch, this only displays green when the door is fully raised. It is not a stop-go signal, as on running lines. It just gives the driver permission to shunt wagons at will in either direction, with assured overhead clearance. This sector plate has been in use for over 15 years, during repeated testing sessions, for many hours of operator training, and at numerous exhibitions. The only problem has been one of the insert strips breaking loose, and it was easily re-glued in place.
Since this article was written, the Gillan and Brown layout has been sold, becoming privately owned. The sector plate described continues to function in its new home.