After reading Silver Sideline's excellent account of his Mainline and Bachmann split chassis locos,  I ran 3 that I had from years ago, and still run ok.  So far, so good.

However, I have a couple of Mainline Scots that have been in the bottom of a spares box for many years.  They belonged to the  late uncle of a friend who gave them to me in a bundle of equipment,   part of a swapping session between us.

One has a complete chassis,  but I couldn't remember it running, the other has broken valve gear one side but 20 years ago or so I had had that one running.

So I though perhaps with very little effort I could have a working loco for nothing. This shows the broken valve gear.

So I started with the complete chassis, took the keeper plate off and cleaned up the wheels and plated parts of the axles.  Smear of Peco electrolube on bearings and lubricated gears motor bearings valve gear etc.

Gave it a run, actually ran fine up and down the layout, then.....oops!

Not only did the rear driving wheel drop off, but a wire running through the plastic axle had sheered.

The other chassis, with the broken valve gear, was in a much better condition, with the plating on the axle stubs having much less wear.

So I could just take the valve gear from the chassis with broken axle and replace the broken set, or just put them back at the bottom of the box...probably worth one more go though!