2009 trackmaster Rocky battery cover

I just got off EBay a 2006 Hit Toy Rocky with all 3 cars. Only the crane is motorized. I bought as "not working". I opened the battery car and found. a terminal wire broke and same was broke just past coupler under the crane. I removed all screws from crane car base but cannot remove the base. Don't want to force it off, any help please,tks