here is a page with some short blips about the SF Muni trolley busses. They are called "articulated" busses. The new ones are designed by Hubner.

If you guys really want to know the details, just call Mike Hursch (sp?), 415-401-3118, the Chief Engineer of MUNI. I called around Muni a few months back because... well, here's why. He's a really nice guy and can tell ya what you wanna know or direct you to someone who can. Sometimes the web can't answer everything. =]