I will explain the lighting system for the Lines/Triang No.30 house. It only has one light, so it keeps everything simple. This is the back of the house showing the position of the wooden lighting panel and the hole in the roof for the battery.
Underside of the wooden lighting panel. The panel works on a wiring system that turns on the light bulb when the metal bar is turned to complete the circuit.
The wire goes from the battery connector  to the tabs  at the back of the flat metal bar. This completes the circuit to turn the bulb on and off.
The bulb holder is connected to the battery connecter  with a wire  that goes through a hole on the base. A second wire  attaches to the connection on the underside of the holder. The wire  then connects to the fittings on the back of the small round metal plate. The battery holder is held in place with two small nails on the remaining holes. [The holder in the picture has the nail through the same hole as the wire.]
Showing the connection on the base of the bulb holder.
Pictures show the different parts of the bulb holder.
The bulb holder measurers 14mm across and takes an E14 pea bulb [also known as a MES bulb, Miniature Edison Screw] For more information on bulb sizes read this article.
The bulb original bulb holder in the Triang houses do not seem to be available now. The picture below shows the new style holders.
LINES BROS. Ltd., London, England.
The Electric Fittings on this toy have been tested before leaving works.
The Battery is easily inserted in holder by
lifting retaining spring. Please see that
Battery is inserted the correct way, so that
contact strips make connection with leads.
No Battery is included but standard flash
lamp batteries are universally obtainable
at small cost.
This is a 4.5 volt battery, it measures 66mm x 62mm x 22mm.
The 3R12 zinc carbon battery is used as a cheaper alternative to the alkaline 3LR12 battery, especially for low-drain devices. As it will probably only be used occasionally a 3R12 battery, is suitable for lighting.
I remember when I was younger having a bike lamp with this battery in it. It seems to be much smaller than I remember, but then I was small to.
This shows the cardboard storage box in the roof space for the battery.
These two pictures show how the battery is connect to the lighting panel. When it is fitted properly in the house the longer metal strip on the battery will be bent in half around the metal tabs. This will hold it in place.
If there is anything you think I have missed off, that you may need to complete this project leave a comment. I can then add the information to this post.