With the axle guards fitted it was time to look at the compensation units. As Tony has pointed out, the WEP units are only one of various kinds on the market, but for commissions which would normally require a solid chassis I find the WEP units are unobtrusive and go together with a minimum of fuss; simply fold up, and using an engineer's square to keep everything as it should be, a couple of dabs of solder from a hot iron fixes everything in place.
The bearings fit in the etched holes without the latter needing to be opened out, so once the solder's flashed around the edges a quick clean to neutralise the flux and the rocking units can be assembled by opening the holes to 0.9mm and pushing the supplied brass wire through, securing it in place by bending the ends to 90 degrees.
I rub the backs of the wheels on some 180 grit wet & dry in a circular motion to remove any casting pips and ensure the backs are flat and true, then give the tyre fronts, treads, backs and axles a rub over with a Garryflex block (grey - medium grade), finally degreasing the wheels and axles with cellulose thinners before chemically blackening them.
There's often a lot of hand-wringing about this process, but it's really very simple. Chemically blackening really is a misnomer (or should be) because that's not what we should be trying to achieve. How many prototype wheel treads are black? Exactly. What we should be aiming for is to tone down the bright shiny chrome steel of the wheels as supplied to a scale sheen appropriate for our models. I've a bit of a thing against using unadulterated real things on our models without knocking their colour and sheen back a little; coal, brass, copper, steel...how often do we read that nothing looks more like real coal than coal on a model? In reality real coal sitting in a tender or wagon looks nothing like a scaled down version of itself and looks much better for a little waft over with a matt black/leather/gunmetal mix from the airbrush to control the sheen.
But I digress...I dilute Birchwood Casey Super Blue with water in a container to make a 10% solution and have some clean water in another container ready on the side. I lay out some paper towel and drop the axles into the solution leaving each one in there for 20 seconds. Then transfer the 'blackened' axle to the clean water and leave that for 20 seconds before fishing it out and drying it thoroughly on the paper. I then repeat the process with the wheels.
The combination of chemically and mechanically cleaning the steel, followed by brief immersion in a weak solution will darken the steel perfectly without flaking. If things are a little patchy, it's simply down to that area not being clean or grease-free, so repeat the process! I've recently seen concerns written about inserts theoretically plasticising in the solution, but in 17+ years of blackening wheels like this have encountered no such problems. Incidentally, loco wheels treads can be blacked as the process doesn't interfere with electrical pickup.
I give the axles and wheels a quick once-over with a hair dryer then fit a brass mop into the mini drill and buff the wheels and axles until they shine with a scaled down sheen. Some people like to coat them with light oil to keep rust at bay, but I rarely bother as next indignity the tyre faces and wheel backs suffer is a blast with black etch primer.