Looking for any leads to find a 9 tooth plastic pinion gears for a Lionel Coal Tipple 6-32910. The size of the broken one is 7mm long 6.8mm outside diameter, fitting on a 2mm shaft.
Contrary to a lingering rumor, Northwest Short Line, the gear folks, is yet in business. Based on my experience, I would contact them with your data and photo. A quick review of their old catalog pages shows a couple possible gears that are close to your need. Perhaps a discussion with them could lead to the best conclusion. Looking at the photo I'm guessing that the working (toothed) portion of the face dimension (thickness) would be about 5mm?...excludes the solid hub portion. Since NWSL's spur gears are all hobbed from either acetal resin or brass, they won't be able to replicate the hub portion. But either material, acetal resin or brass, will surely survive the press fit over the knurled shaft. If the mating gear is of plastic, I'd select brass for your replacement gear, but they'll give you the best recommendation.
They're at nwsl.com
Good luck...and let us know your solution for the benefit of other Tipple owners.