Robert,
I have a pair of rivets for the whistle/direction assembly. Not sure if I am going to use them or drill-and-tap. I do not want that screw to loosen over time. I cam press the rivet on with the arbor press. I have a pair of parallel jaw pliers that work well for pressing roller pins.
I had to "repress" a couple of the soldering lugs on the whistle/direction assembly. One had completely broken loose (I believe it was channel A, one of the offending channels in the first place). A couple others simply spun around but had not become disconnected. The Hobby Horse press sure made that job doable!
Did you replace the resistor wire and 6-volt lamp with an 18-volt bulb? If so, what wire gauge did you replace the resistor wire with?
Dennis