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Cass 6 Middle
Truck Gears & Shafts
Nelson Riedel, Nelson@NelsonsLocomotive.com
6/23/2004, last updated 07/29/2004
The sketch below shows the gear arrangement for the
two-truck Heisler. (The sketch is taken from a marketing brochure
originally published in the 1920s. The comments below the sketch
were probably penned by a marketer or salesman.) The drive shafts pass over the inner axels to
universals. After the universals the truck shafts slope downward to the
pinion gears. The front and rear truck of the
three-truck Heisler use the same configuration shown here. The middle
truck however must be different; there must be a way to get the driveshaft
through the middle truck to the rear truck. The investigation
of the middle truck was a good excuse for a trip to Cass in June, 2004.
| Cass 6 Middle Truck: This was a perfect time to check
out the middle truck ---- it had been taken off the locomotive to replace a broken
shaft. The photo is taken from the front looking toward
the rear. The brass/bronze lower bearing halves show the
locations of the two shafts.
The photo shows 3 bearings for the right shaft and 2 bearings
for the left shaft. The left shaft has a third bearing over
the rear axel; both the top and bottom of that bearing have been
removed. |
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| This shows the locations of the two shafts and the gears.
The line shaft on the left (right side of locomotive) passes above
both axels and has a universal just in front of the front axel and a
second universal just to the rear of the rear axel.
The pinion shaft and drive shaft are parallel and level or nearly level.
The pinion shaft has a pinion gear that engages the bevel gear on the
rear axel.
The pinion shaft is driven by the line shaft via spur gears on
each shaft in the positions shown on the photo. |
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| This photo is taken from the rear of the truck. The square
notch over the rear axel is where the third (rear) line shaft bearing
is located. Note the oil cups on the top of the bearings between
the gear case and the axel. |
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Line Shaft: The two photos below show the line shaft.
Unfortunately, I couldn't pick it up and position it for a better photo.
Note that there is a universal on each end of the
shaft. There is a bearing on each side of the gear and a
third bearing just in front of the rear universal. I assume
that the bearing caps were removed and the shaft then lifted up and
out. (This was after cross pieces at the top of the truck were
removed.)
Pinion Shaft: The photo below shows the
pinion
shaft. The shaft broke between the pinion gear and the spur
gear when the locomotive was going up the mountain. There
was still power to the front and rear trucks so it was possible to drive
the locomotive back to the shop. The broken ends wore against
each other to make it appear the shaft was cut rather than
broken.
| This is the pinion gear adjacent to the place on the shaft
where the spur gear mounts. Note that the shaft diameter
where the gears mount is 5.1732" The diameter
where the bearings fit is ~ 4.875"
The pinion gear has 12 teeth, 9.5" tooth
length, and a maximum diameter of ~18"
The mating bevel gear has 24 teeth and a maximum diameter of ~
30" |
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| This is the 13 tooth spur gear. It is 10"
long with 14.5" maximum diameter. |
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| Bearings: This is a closer view of the two rear
bearing bases for the pinion shaft. The pinion gear fits
just to the right of the right bearing. The spur gear fits
in the recess just to the left of the left bearing. That's
a tape measuring laying in the bearings ---- one way I use to
record dimensions. The bearings are about 10" long
and the shaft diameter is a little less than
5". |
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| This shows a bearing half and two covers. The cover on
the left has a hose coming out the top for forced
lubrication. The cap on the right has an oil
cup. I didn't record which bearings had forced lubrication
and which had the oil cups. |
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| Gear Cover: This photo shows the cover for the
pinion and bevel gear. There is a similar cover over
the spur gears. Both sets of gears run in oil. |
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| This middle truck sketch was made by cutting and pasting parts of
a two-truck configuration sketch. |
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Jack Stands: How does one remove a locomotive
truck? Easy, jacks and jack stands. The next photo
is taken from the rear of the locomotive looking toward the front.
The blocks are under the middle truck bolster.
This photo gives a good view of where the drive shaft passes under
the firebox between the two ash pits. The small tubes on the
left come from the lubricator that provide forced lubrication to some of
the bearings in the truck.
The next photo of the rear side of the middle truck
was taken a few months before the shaft broke. The drive shaft
on the right side goes to the rear truck. The case enclosing
the bevel gear is near the left wheel. That's a water hose from the tender in the center of
the photo. The chains that connect near the wheels limit the amount
the truck can rotate --- I assume if the engine derails. I
think the chain closest to the camera loops under the drive shaft and keeps
it from dropping to the ground should something come loose or break.
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