[MrFlippant]

Solder is not flexible, and will break after enough flexing of cars running over the joint, and temperature fluctuations. Same with tape. Tightening the joints has a similar life span. That's why I finally decided to do the little jumper wires. They allow the flex and expansion, and the quality of the joint of the rails is more or less unimportant. It's a lot of work, and I would not recommend it to anyone who is still changing their layout, or otherwise not ready for it to remain the same for a long time. But, once you're at that point, the work is absolutely worth it.