Please note that if using flexi-tube in place of copper tube the methods described below may vary slightly.

How it works
Anyone who is familiar with the brakes on a bicycle, operated by a Bowden cable, will understand the principle behind a wire-in-tube system. A fine wire, attached to a lever at one end and the point tie-bar at the other, moves inside a tube which directs the wire and keeps it rigid. Changes of direction are accomplished by bending the tube to follow gentle curves. If sudden changes of direction are required, these can be achieved with angle cranks.
The tube can be mounted above or below the baseboard, although in the latter instance the movement will need to be transmitted up through the board by means of rods and cranks. It is best used on the baseboard surface and installed as the trackwork is laid. Once laid and set up all the visible tube can be covered with scenery.
Decide how the tube is to be situated on the surface i.e.

a) Laid directly on the surface and secured by pins etc. (see later)

b) Laid in grooves cut in the baseboard surface. These can be covered with thin card which then forms an outer tube before any scenery is laid.

c) If the baseboard is covered with cork underlay, grooves cut in the cork act in the same way as cutting into the baseboard.

Planning
It is always a good idea to work out what you are going to do in advance, estimate the materials you will need and order accordingly.
Having decided where the levers will be situated, the next job is to plan the runs of tube between the levers and the points. For best results the tubes should not cross over one another and the curves kept to a wide radius.
The positions can be marked on the baseboard with a marker pen. Any angle cranks that are needed where the curve is too small can also be marked on the baseboard in the same way to ensure clearances. All planning should be completed before installation begins. This will prevent problems with tube runs later.

Installation
You will need to have a sequence for installation, and if the track is to be ballasted using loose ballast and PVA glue, all point controls should be in place and operating correctly BEFORE ballasting begins. It is best to start with points at the furthest distance away from the levers so that other track is laid over the tube after it is fixed. This should alleviate the problem of lifting existing trackwork to install the tube.
Begin by inserting the wire into the tube until it protrudes from the other end. If the tube is to be bent always insert the wire before bending. This will stop any tendency for the tube to "kink". Bend the last 5-6 millimetres of the wire at 90 deg. to form the operating end which fits into the point tie-bar from the underside. On a Peco point the wire can be looped around the spigot on the end of the tie-bar or the spigot removed and a small hole drilled through the end of the tie-bar (recommended). Once in place and operating correctly any surplus wire protruding above the tiebar can be bent over or cut back. Once the wire is located in the tie-bar, position the tube following the lines marked on the board at the planning stage. If the lenth of tube needed is longer than a single piece just butt the two ends together. As long as the tube is fixed firmly and cannot move it is not necessary to physically join the tubes together. Ensure that there is no gap between the tubes which would allow foreign matter to enter if laying scenery over the tube. Tape or thin card is ideal to cover the joint. There are various methods of fixing the tube to the board :-

a) Small wood blocks, drilled and pushed onto the tube as it is laid.
b) Brass countersunk screws to which the tube is soldered to the head.
c) Brass pins alongside the tube – tube is soldered to these.
d) Miniature eyelets screwed into the board through which the tube runs.
e) Staples as used to fix cables to walls.

When the tubes have been fixed in place bend the other end of the wire as if you were attaching it to the point. This is then inserted into the lever and the lever fixed to the board. If using a leverframe the wire is bent so that it runs parallel to the board and if using the Universal Point Lever it is bent at right angle to the board. The end of the wire should then be bent round to form a tight loop. Always ensure that the wire connects to the levers / points in a straight line to the travel of the lever / tie bar.
Once everything is fixed in place test the operation. Any loss of travel is usually because the wire or tube "flexes" sideways. This can be rectified by finding where the "flexing" occurs and adding additional pins to eliminate it.
A small amount of sideways movement can also be used to take up any over travel on the leverframe. With the Universal Point Lever the travel is dependent on the movement of the point, so always ensure the lever is vertical at the mid-point of travel of the point. Excessive travel in the leverframe as opposed to the travel in the point will require the use of an Omega Loop between the lever and the wire. One end of the Omega wire is connected to the lever and the other end attached to the wire using a "Wire Snap".