re-attached pickups on Lionel Classic

I have a Lionel Classic #325 Observation car where the pickups were poorly rivetd at the factory. The rivets have fallen out and the pickups dangle fom the wires. I don’t have a pop rivet tool small enought to re-connect them to the axel bar. how do I re-attach them?

I don’t know exactly what kind of trucks you are talking about; but I haven’t found a rivet yet that I could not replace with a machine screw and a nut.