Landing three or more Bonus Scatters anywhere on the reels in the Money Train 3 slot activates the crucial Money Cart Bonus feature. You will benefit from the persistent (gold) symbols, which can also act as the Bonus Scatter when the feature is activated.
Every triggering symbol turns sticky and reveals a multiplier value for your bet that ranges from 1x to 10x  your initial wager. Then 3 respins are granted. Before the first respin, the action of any persistent symbols you had when the feature was activated will be revealed. It becomes sticky when a new symbol lands, and the respins counter resets to three.
In addition, when you fill a column with symbols, a new column is created. Throughout the feature, this might happen twice. These unique symbols can also appear with bet multiplier symbols worth up to 10x the bet.