There are several questions regarding design patterns that apply to infinite scroll such as What's the design pattern at the end of infinite scroll? and also What are best mobile navigation practices for infinite scrolling pages with a deep hierarchy?
However, my question specifically applies to design patterns that help indicate where the user is currently located within an infinite scroll section of a page, which is often simply handled by the same page scroll bar. While this is a solution to the design pattern, it exists by default and isn't designed specifically to handle this issue.
There are also instances of two scroll bars on the same page, which causes some confusion with users, not the least of which exists on the mobile page views of having to manipulate two scroll bars in a very limited space.
Are there good examples of how infinite page scrolls are handles in a web or mobile application that provides clear indication of where the user is currently located and allows then to navigate the content?