Mikado problems

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flightcase
Posts: 4
Joined: Tue Jan 05, 2021 4:05 pm

Mikado problems

Post by flightcase »

Earlier this year I bought a Broadway Light Mikado which after quite light use has now fallen to pieces quite spectacularly, with coupling rods pointing in every direction bar the horizontal.
As a newcomer to n scale I’m loath to start dismantling it for fear of causing more damage. Can someone please tell me whether kind of fault this is normal, and how resilient these locos are to indelicate handling?

Eddie.
barry10
Posts: 3
Joined: Tue Jul 27, 2010 12:54 pm

Re: Mikado problems

Post by barry10 »

Hello Eddie

I've not had this problem with my own BLI Mikado, but it does sound similar to one I've had with the Bachmann 2-10-2s. With these, the return crank works its way out of the centre driver and then everything ends up as you've described.

With the 2-10-2s, the fix is pretty straightforward. Unscrew the keeper plate (I think the BLI locos have a similar design), set it aside, and then lift the individual wheelsets out of their bearing slots, get them back into quarter with respect to each other, then lower them back into place. With most N steam locos, some of the wheelsets are connected to the coupling rods, and some are just geared to each other. The ones that aren't connected to the rods will still have a moulding of the balance weight on, so it will look better if these are properly aligned as well. Hopefully, the individual wheelsets will still be in quarter, but if not these will need adjustment.

Once you've got everything straight, with the coupling rods all level and offset by ninety degrees from the position on the other side, the keeper plate can be screwed back on. Now, assuming the return crank retaining pin is loose or slipping, you can address the connecting rod and the return crank. To stop it working loose again, remove it (if it's not already fallen out) and add a small amount of epoxy into the hole in the driving wheel. Position the connecting and return cranks and press the pin home again. With the coupling rods at bottom dead center, the crank should lean forward very slightly. Assuming five minute epoxy, I gave my locos a very gentle test run in both forward and reverse to make sure nothing was binding, then allowed the glue to set.

The initial problem was caused by a slight splitting of the plastic in the main driver where the crank pin fits, allowing it to work loose. If the mishap with the BLI loco is due to some other cause, the crank pin may go in firmly enough not to need epoxy.

Hope this is some help.
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