Disgusting 1950s RS3 Locomotive - Can We Make It Run?

I picked up this 1950s die-cast Hobby Town RS3 locomotive on eBay over a year ago in a scrap lot. It appears to have been poorly assembled and the gear boxes were absolutely disgusting as they were packed with dry grease and dirt. This is a challenge in comparison with what I usually work with but with a bit of effort, can it run again? Fiberglass pencil: https://amzn.to/2VeB6CU (affiliate) USA