How about a step by step procedure Mark?…desoldering the rods is the easiest way. You can dismantle the engine to get to the tires, but it is a lot simpler to just touch them with an iron and pop them off,….follow the order …
1. remove boiler shell
2. rotate motor by hand so one eccentric is at the 6 o’clock position. Note orientation ( direction eccentric rod faces )
3. hold eccentric with tweezers or needle nose pliers at the small end ( end with the link rod )
4. touch big end of eccentric with soldering iron while lifting upwards.
5. swing eccentric out of the way, lift rod and any spacers off crank pin. ( note how rod & spacers are oriented on crank pin ) you may have to loosen connecting rod bolt on front driver to lift it high enough off rear driver crank pin.
6. replace traction tire
7. place rods & spacers back on crank pin in their correct orientation.
8. grab eccentric with tweezers or needle nose with one hand, and the soldering iron with the other.
9. set eccentric over crank pin in the correct orientation as stated in step 2
10. touch eccentric big end with soldering iron to melt solder, and it will “fall” back in place.
11. inspect your work. Hold locomotive up and make sure the now freshly soldered eccentric is square …ie; the eccentric face should be parallel with the wheel face. In other words, make sure you didn’t solder it crooked
12. test run engine BEOFRE proceeding to the other side.
13. if step 12 was successful, repeat procedure on the other side
14. job done, prepare peanut butter & jelly sandwich & a glass of milk, ….enjoy