Re: Photo: Boiler On NYC Flatcar
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Agreed on the “no rusty wheels”. I’ve been working on prototypically modeling/weathering wheel faces for solid bearing trucks recently. Every time I think I have an accurate and easily reproducible method, I find another well-lit photo illustrating some new oil pattern. In this case, it was the radial streaking - different than the more common “soft” circumferential wicking from the hub outward and tire inward.
This wheel face is relatively clean - maybe there simply hasn’t been enough dirt/dust yet collected to absorb and distribute the oil more evenly. In any case, another well-lit reference.
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On Jul 21, 2020, at 10:27 PM, Dennis Storzek <destorzek@...> wrote:
On Tue, Jul 21, 2020 at 05:09 PM, Matt Goodman wrote:
The radial lubrication streaking on the left most wheel face caught my eye. Probably from a leak through the rear seal while standing still.Solid bearing journal boxes don't really have seals... the rear opening was closed by a "dust guard" which in the period of this photo would have been wood.. The oil level was maintained below the level of the axle. if the box was over filled, the excess quickly ran out the back. In operation, capillary action brought the oil up into the ball of wool yarn "waste" (short strands of yarn of no use for weaving) where it wetted the exposed bottom of the axle. When the axle turned the oil was drawn in between the axle journal and the journal bearing, and the car actually rode on a film of oil. This was a "total loss" lubrication system, as the oil spread across the journal it came out both the front and back edges of the bearing, which were shoulders that acted as thrust bearings to keep the truck aligned with the wheels. The oil that crept out the back was flung out and ended up on the face of the wheel, which is why there are no rusty wheels during the steam era.