[HayZee518]

Track Lighting manufactured by McGraw-Edison and Lightolier look the same but are connected differently. All make contact along the sides of the track by stabs that press against the conductors mounted in a plastic channel that run the entire length of the channel. Multiple lengths use a junction stab to make them longer and use the same pressure principal. Same with the right angle direction changers.
Loose wires feeding them, open feeder stabs and spreading channels contribute to faulty operations. A lot of times, overloaded conductors expand from heat where poor contact is made with the receptacle [fixture] plug ins. This causes a high resistance which gets worse as time goes on, eventually nothing works. Here's a rough diagram of a typical track system.