It it permitted to place charity boxes on the streets and bus stops or is it gezel of the rabbim?
Provided there is no potential of damage caused to the public, such as a metal box with a sharp corner that is liable to damage, it is permitted. I know of a case where a charity box was tied to a tree too tightly, and this caused the tree to die, thus care must be taken.
Sources: The Gemara mentions in numerous places the prohibition of digging pits in the public domain, and similar actions that are liable to cause damage. The implication is that with regard to action that does not damage or disturb, no prohibition is involved. The public domain is meant for the public, and this can include charity boxes, provided they cause no harm. However, if local or national laws prohibit this, the law must be abided.
If the bus stop is private property, the provider should be asked for permission before affixing the charity box.