For modelers working in O Scale, there is a collection of Swan Neck and Industrial Building lamps together with a range of fibers and connectors, and 2 different sizes of lights sources, the Lamplighter™ boxes. The Ind. Bldg. lamp is designed primarily for HO scale, but some O scale users have also found this useful on some of their buildings.
The Lamplighter boxes come in two sizes, the Lamplighter 2 box which is the larger of the two and N scale folks are buying to light their complete layout, and the Lamplighter 1 box which is for smaller sections or small layouts. Note that the Lamplighter 2 box provides 30% brighter light than the Lamplighter 1 box.
The best fiber to use with this gauge is the 1.5mm fiber as it provides plenty of light for buildings. The various fiber diameters provide you with a collection of different intensity lights and different flexibility of fibers. The 0.5mm fiber is well suited to applications such as lighting cars, trees, etc. Note that the Swan Neck lamps come with 3+ft of 1.0mm fiber and the Ind. Bldg. lamps come with 3+ft of 0.75mm fiber.
If there is a need to connect fibers together, there are Fiber Connecting kits that are suitable for connecting 1.5 to 1.5mm, and 1.0 to 1.0mm fibers. They can also be used to connect different sized fibers together, such as multiple 0.5mm fibers to a 1.5mm fiber. This is useful when lighting small objects such as car lights using 0.5mm fiber but then running a 1.5mm fiber back to the Lamplighter box.
What to buy for a first order:
A Lamplighter 1 or 2 Starter Kit which will include 30ft or 60ft of 1.5mm fiber.
Add lights now or later. Add 1.0 fiber and others to experiment with.