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Mickey Poppo Gearbox Repairs

The "Mickey Poppo" is a roughly American style steam locomotive first released in red and green in late 1982 based on the Western River Railroad in Tokyo Disneyland as some of Plarail's first licensed toys. These trains originally used a cramped old power friction-drive gearbox with clicking mechanism that was produced in both Japan and Thailand. In the later 90s a new power gearbox was developed and the tooling was also used for Shuppo and the rereleased Plarail Day Benkei. In the 2000s a series of Tokyo Disneyland sets were released that updated the engine to use a AA battery and later an entirely new gearbox with the AA battery now also located in the engine itself.

One common problem with both the old friction drive and the 90s axle drive C battery trains is that the wire from the tender to the locomotive can be broken by children easily. On old power trains the friction drive gearbox is commonly very dirty and in need of new rubber components and the new power gearboxes are now suffering from cracking gears as the plastic contracts with age. Additionally, they are often missing the somewhat loose friction-fit tender battery covers. I have recently (March 2024) modeled a 3D printable replacement cover.

Opening Mickey Poppo

Both old and new power Mickey Poppos have a single screw at the front that holds the cowcatcher and front wheels in place. After removing this screw, the cylinders can also come out. On new power Mickey Poppos, an additional screw at the rear of the chassis can be removed and the smokebox and bottom of the chassis will come free and the rear wheel can be taken out. On older Mickey Poppos the rear wheels are actually pressed onto the axle around the chassis and gearbox and can not be removed without pulling one of them off the axle.

The body shell on both of these styles of chassis is held in with two small clips on the side of the chassis that slot into cutout divots in the cab behind the Mickey or Donald stickers. Using a screwdriver or some other method, you need to either bend the walls of the chassis out and around the tab or push it in against the chassis slightly (or both) so that it can come unclipped one side at a time.

Old power gearbox

The old power gearbox in these engines is more cramped and exposed inside the relatively small locomotive and is often dirty and almost always in need of new rubber components. A plastic "cap" sits over the gears and includes a small bent metal strip that creates a clicking when run, similar to the chuffing gimmick on Japan-made C12 and D51s. This was the only clicker noisemaker that survived the transition to Thailand production. The contrate gear on the first shaft reduces the drive from the motor and transmits it to the drive shaft with the rim-drive rollers through another reduction. An odd metal cog embedded into the drive axle rotates a free-spinning gear with cam around the first shaft which hits against the clicker.

The rim-drive spools will most likely need to be replaced. The tires on one of the Mickey Poppos used for this pictorial were badly worn and pitted, so I removed them and replaced them with several layers of heat-shrink tubing, while the other had more even wear and was wrapped in a single layer of heat-shrink. The wheel tires will most likely also need to be replaced. The best way to remove the wheels if needed (which I ended up doing on both of the pictured toys if only to clean up the axles and chassis) would be with a pinion or wheel puller type tool which will brace against the back of the wheel and push the shaft out, but if you are careful the wheel can be removed with a combination of gripping the wheels with both hands and pulling apart while twisting slightly or wedging the wheel gently away from the body, rotating the wheel as you go.

New power gearbox

In the later 90s after production had moved to Thailand the Mickey Poppo chassis was changed to use a "new power" axle drive gearbox. These engines had cab power switches and somewhat easier serviceability. This gearbox is also used in the Plarail Day Benkei rerelease and the Adventure Asphalt Island Shuppo trains, which use the same tooling.

The new power gearbox has two screws on one side that must be removed. There are three shafts inside the gearbox. A contrate gear on the middle shaft with an integrated spur gear drive a larger gear on the upper shaft which is spring-loaded and slides in and out of position with the power switch. Another gear on the upper shaft reduces with a free-spinning double gear on the middle shaft which reduces with the large gear on the lower shaft. A pinned idler gear in the other half of the gearbox casing transmits power to the rear axle.

On the upper sliding shaft the smaller ten-tooth gear near the spring contracts and splits. The other ten-tooth gear on the bottom axle also splits. These can be replaced with the same 10 tooth gears for 2mm shafts used in several other Plarail geartrains. The original gears have a shoulder on one end, but this is not necessary for operation.

Tender wiring

The negative side of the battery contacts the rear terminal and passes through the power switch (either in the tender or later the gearbox). The remnants of the power switch exist even in the modern AA version of Mickey Poppo's descendants.