This whole project started when my brother decided that my kids needed a vintage Tyco Trucking US-1 set for Christmas.  We live in different states, so he decided to order a bunch of stuff on e-bay and have it shipped to my house.  A few days before Christmas, I started going through the stuff he had ordered, and realized just how much was needed to get these up and running.  

The main things I ran into at first were:

• The rubber on the rear tires is falling apart
• The copper pickups on the bottom are in bad shape
• Some of the motors are pretty weak
• The track has some corrosion/ rust on it
• A lot of stuff has been in storage in garages/ attics for a while and is just dirty

Luckily, there are solutions for all of these. 

• You can find replacement tires on e-bay.  There are custom ones made out of silicone that work well.  Also, there are some rubber ones that I haven't tried yet.
• Some awesome guy is making replacement copper pickups.  You can find them on e-bay or at his business: http://www.slotcarcentral.com/  (They're cheaper on his website, but I didn't find that until after I bought them on e-bay)
• You can buy replacement motors on e-bay, but I also have found that you can "recharge" the motors' magnets by pulling the motor and sticking a bunch of neodymium magnets on each side for a few days.  This is a lot easier than disassembling the motor and buying a magnet "zapper" that you can apparently use.  That might work better, but the neodymium magnets seem to work pretty well to me.

• The track can be cleaned using the green scrubbing pads you use for washing dishes.  These scrubbing pads also work well for cleaning the copper pickups, which will need regular cleaning to keep everything running smoothly.
• As for cleaning the dirt-- a lot if it I just threw in a sink and scrubbed with soapy water.  Doing this once doesn't seem to cause a problem with corroding the track, but I wouldn't want to do it often.  

Oh, and there's one more big issue.  Early versions of the cars were made with brown gears.  Later versions used white gears.

The brown gears are awesome.  The white gears, however, haven't stood the test of time so well.  Most of them are cracked.  I went looking for replacement gears and couldn't find anything.  So, this being 2021, I opened up some CAD software and went to work.  I'd never designed gears before and designing mating worm and spur gears was an interesting challenge.  A few weeks later, I got these back from Shapeways:

For about $20 including shipping, I now had 9 new gear sets.  And as it turns out, these work really well.  I've been using them in a few cars for about a month with no issues.  You can find the STL here: https://www.prusaprinters.org/prints/55302-tyco-trucking-us1-gears

As a side note, before I got these back from Shapeways, I saw that someone else has designed replacement gears and is selling them on e-bay.  It's good to see alternate options out there and others keeping this awesome toy working.