To be "with the group" or to "be cool" as determined by your peers. The "trolley" would be something one would want to be on.

One may also want to make it a point of saying that someone is not on the trolley, instead of just saying that they should get on it. This implies that the person is so uncool that they cannot even try and be cool.

Another popular use is pointing out that a particular member of your friends circle is on the trolley in an attempt to rub it in the face of the person who isn't.

This phrase is usually used in a ribbing manner towards friends.
(After making a faux pas, doing something the group would consider uncool, etc) Come on Jason, get on the trolley.

Adam is definitely not on the trolley.

See Ryan? Now, Austin is on the trolley.
by mamushi November 20, 2006
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similar to "got off my kool aid," but with way more Italian jealousy. When an absolutely gorgeous redhead is involved, an Italian guy would say "get off my red trolley!"
by Not-A-Competition January 26, 2013
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