The following sentence is taken from a recent “Friends of 261” newsletter: “The drivers were sent to a local company near the shop where they will be quartered and the tires turned.”
I understand the turning part, but what is “quartering” and how is it done?
Quartering is making certain that the crank pin centers on the ends of a driving axle are exactly 90o apart. This is done so that the rods on one side will be 90o, or a quarter turn, out of phase with the rods on the other side. Thus, if the drivers on one side are dead-centered (either as far back as the rods can go or as far forward as the rods can go) when the locomotive is stopped, the drivers on the other side will be able to start the engine moving again.
It is done very carefully. The 1922 edition of Locomotive Up to Date gives two methods, one of which seems simpler to use, but it does require quartering a new axle (pp.758-9). Essentially, the axle is set up in a lathe, a line is scribed on the right end; this line is used to locate the right keyway. Then, the axle is carefully turned exactly 90o, and a line is scribed on the left end of the axle (this sequence will assure that the right side precedes the left side when moving forward). Once the locations of the keyways are determined, the keyways themselves are cut. The other method described (pp.738-740) can be used with an old axle and new wheels, or with a new axle and new or old wheels.
Regardless of the procedure followed, the work is done, as I remarked, carefully.
Actually, I should have said that the crank pin centers on the two drivers on one axle should be exactly 90o apart; the crank pins are not on the axles, but on the drivers.
Another note on quartering: If the axles aren’t changed, there is a device that can actually machine the crankpins while they are in place on the wheelset. It is specially made just for this operation, so the crankpins are quartered correctly. Either new crankpins can be installed and the machine finishes them to size, or existing crankpins could be machined undersized and new rod bearings machined to match. The result is the same regardless, minor problems with the quartering can be corrected with this process. IIRC, there are only a couple of these machines left in the states. I would assume that 261 is getting new axles, but that is just a guess. If so, it will follow the procedures that Johnny referred to.
I’ve been through the quartering process on “Live Steam” rideable locomotives; that is stressful enough. My hat is off to those who are able to do this kind of machine work on a full size locomotive!
In the video/DVD series about the restoration of CPR 2816 11 years ago, the same thing happened, and the narrator said the same words…turned and quartered. Each of those driver/axles weights 8 tons, so it isn’t just a matter of two guys grabbing an end and hoisting them onto a lathe.
If I recall, the driver sets were sent to the Tennessee Rail Museum, or a name close to that, because it was one of the two or three places in N. America with the machinery and expertise. They did a bang-up job, too. On its few trail runs, 2816 had only one hot bearing, and it ‘rode up with wear’, to use the phrase from Are You Being Served?
-Crandell
one minor headache affecting quartering; the mighty Pennsy quartered its drivers with the LEFT hand leading! also, i believe the 3-cylinder machines such as up sp 4-10-2’s were ‘quartered’ at 60 degrees, with the crank for the third cylinder at 60 degrees to either set of side rods. -big duke
Doesn’t quartering have more to do with smooth running than starting from bottom or top dead position? As long as the crank pins on alternate sides are aligned the same and not 180 degrees off, the locomotive can start. If the cranks are not all aligned the same then then 1) the rods will fit on one side but not the other of the locomotive and 2) the locomotive will go chugg-chug-chugg-chug with the power applied unsteadily.
Combo of both actually. If you have a set of Drivers out of Quarter your going to risk blowing out a cylinder or valve gear. Worse case would be breaking a Main Rod when the Other side starts to come back when the other side is still coming Forward under power. Also your going to tear the HELL OUT OF THE TRACK.
The problem with what you are envisioning is that the valve timing, the lead, doesn’t lend itself to the reverse/forward control if the crank pins are anywhere near 180 apart. When they are offset by 90 deg, one of the valves always has an inlet port uncovered so that steam can enter the cylinder and act on the face of one of the pistons. Due to my lack of expertise on this subject, I may not be using the precise terms, nor the correct technical details, but there was an absolute reason for having them quartered, and it was so that the engineman could use his reverser to make the engine do what he wanted from an absolute stand-still.
-Crandell
If you check closely pictures of the 9000 at Pomona, you will see it is quartered at 120 degrees. The third cylinder is probably quartered at the third 120 degrees position. It would be out of balance at 60 degrees.
Thanks to Cowboy station for pictures.
Left side of 9000
http://www.cowboystrainzstation.com/up9000-016.jpg
Right hand side of 9000
That would be true, if the center cylinder weren’t inclined 9.5 degrees.
You have a valid point but listen to the recording. It is not in equal chuffs.
If you listen to the recordings of the 9000 on that page, you will hear the really off beat third cylinder sound. I am not sure if that is because it is quartered on a 120 degree offset and in addition has the incline. I have not looked into the third cylinder offset since it is on a crank on the second driver. It would be interesting to know the exact degree set of the crank of that third cylinder compared to the other two.
The third cylinder 27" x 31" while the main cylinders were 27" x 32".
Thanks and credit to Utah rails for this sound of the 9000 series.
Well, I guess that the PRR people had not read The Locomotive Up To Date. Apparently, there preference did work. [:)]
I cannot explain what is stated in the book; I can only report it.
[#oops]When will I remember to proofread thrice; it’s their, not there preference.