Southern
Pacific
1218
Wheel Profiling
Wheel Profiling
The wheels on our S6 were horrible. The flanges were too high, the treads were badly hollowed out (which means that they were shaped like a pulley) and there were some pretty severe flat spots. They were also afflicted with the tread crawling out over the edge of the wheel. The only saving grace was the fact that the wheels had enough material on them to allow profiling. We have a gadget called a "Iron Horse Wheel Lathe which provides an economical means of turning wheels. The process is a bit labor intensive but the results can return a wheel to a legal contour.
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To start, the 1218 had to be positioned on a stretch of track where it could sit for a while as some jacking is necessary. We had to jack the locomotive weight off of the truck to prevent undue wear on the axle journal bearings. Next, the brake mechanism on the operative truck was disconnected and the brake swing arms removed. The traction motor is jacked up about an inch above the rail and then the lathe is mounted to the rail, leveled, and secured. Usually, the motor leads would be disconnected and connected to an arc welder but, due to the way the S6 is wired, I decided to simply disconnect the main generator, connect the welder to the existing electrical system in the locomotive and spin the motor just as though the diesel engine were running. I built a "remote control" box which is a simple toggle switch in a box connected through a cord to one of the power contactors in the locomotive. This allows me to instantly turn the power to the motor on and off. Of course, safety required that the truck still on the ground would have its brakes fully applied so the 1218 was connected to the house air compressor. For a short movie of the lathe in action, click here. (Note: The sparks in the video are due to the extremely hard carbide cutting bit hitting the very hard old wheel material) Photo #4 illustrates Jon and Rich disconnecting the inside end of the straddle bars which connect the left and right brake swing hangers on each wheel. This is not all fun and games.
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 Jon Vlasak Photo |  |
The cutting process produces a lot of steel wool. Photo #1 is of the cuttings from 2 wheels. This was an unusually large amount because one wheel was larger in diameter than the other and had to have some of the tread cut off. This forces the cutting of the flange to a new profile. The wheels on the same axle cannot vary more than plus or minus 1/4" in circumference. Just before cutting started, the wheel would be "taped" to determine its circumference. Photo 2 shows the tape checking the final cut on the tread before starting to cut a new profile on the flange.
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