Pacific Railroad
Preservation Assoc.

Turning the Drivers, Part 2.

Attaching the Counter-Counterweights.

Each driver is counterweighted to balance the rods attached to it and its own crankpin. The 4-8-4 configuration has the same size counterweights (at least to the eye) on the #1 and #4 drivers and differing sizes on the #2 and #3 drivers. That's because the amount of rod weight they are countering differs. The #1 and #4 drivers have just one rod, the #3 has two rods, and #2 has two rods plus the main rod plus a much larger crankpin.

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Tom Weisner takes a moment to think over the process for attaching the weights to the #2 driver. As you can see, the counterweight on this driver is enormous, covering almost the top half of the driver. In the background to the right, note the smaller size of #3's counterweight (sitting at about 4 o'clock) and #4's (sitting at about 6 o'clock). Also, note the much larger crankpin on #2. Photo by Terry Thompson.

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The attached weights were used in different combinations for #3 and #4. Number 2 will need them all and more. Photo by Terry Thompson.

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Here's the final weighting for #2. Besides the attached weights, the bearing has been slipped onto the crankpin. Photo by Terry Thompson.


Driveshaft

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The above photos were taken on the fireman's side (left side). Now we're on the engineer's side where the drive shaft is attached to the #2 driver. Tom is finishing the attachment for this driver. The driveshaft was described in Part 1. Photo by Terry Thompson.

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A wider view. The large housing on the right is the 195:1 reduction gear. Photo by Terry Thompson.

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A worker in the pit is smoothing the inside of the rail prior to attachment of the heavy plate that spans the rails. Photo by Terry Thompson.

Turning the Drivers - Part 1

Turning the Drivers - Part 3