[Motorcycle Jack]

The reason your switch is getting hot is because the track lighting is drawing too much current. Going from 50 watts or bulbs that draw 4 Amps to 35 watts or 3 Amps is not much of a change - 6 bulbs would mean only 6 Amps difference. What I suspect is that the track to light connection is dirty - since you've never cleaned it in 7 years. I would take the track down, clean the electric slide portion with some emery paper and also the slide contact from the light. Dirt or corrosion on these can change the resistance by hundreds of ohms and increase current draw but 10 -15 Amps or more.