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 Post subject: Driving Axle Diameter
PostPosted: Wed Aug 07, 2013 6:15 pm 

Joined: Sat Apr 15, 2006 9:55 pm
Posts: 252
Location: San Diego area
In the FRA Steam regs, 230.98 (b), the "original/new journal diameter shall be stamped on one end of the axle...." And, 230.98 (a)(7) condemns axles that are worn more than 3/4 inch or more below the original/new diameter.

I'm looking at a 1929 ALCO 2-8-2T for possible restoration. How do I know what the original journal diameter was? The end of the axle is stamped thus:

ALCO
H-51213
S-2120
5

with a large R to one side of the other numbers.
None of that looks like a diameter, although maybe the old regulations didn't require the diameter stamping.

Thanks for any advice you can give me.


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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 07, 2013 6:26 pm 

Joined: Fri Jul 23, 2010 12:41 pm
Posts: 377
Location: Minneapolis, MN
Back in the day there was no requirement to stamp the original diameter on the axle. You can find the original diameter, however, by researching the ALCO standards. You will find tables of driver sizes and corresponding axle diameters. When you measure your journal diameters, they must be greater than the original diameter less the 3/4 inch. I have been helping with the rebuild of the Saginaw Timber No 2, a 1912 Baldwin 2-8-2, at Mid-Continent Railway Museum and we had to look in the Baldwin standards for the original axle diameters.


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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 07, 2013 7:24 pm 

Joined: Sun Oct 19, 2008 12:58 pm
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Location: Chicago USA
If an axle is turned is it ever turned in the middle? Seems like only the journal and wheel mounting areas would need to be turned.

Steve


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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 07, 2013 11:33 pm 

Joined: Fri Jul 23, 2010 12:41 pm
Posts: 377
Location: Minneapolis, MN
I suppose an axle could be turned in places other than the journals, but usually only the journals were turned and resurfaced. And the forging was usually very rough between the finished journal surfaces. I suppose that measuring in the center of the axle would give you a rough estimate of the original diameter.


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 Post subject: Re: Driving Axle Diameter
PostPosted: Thu Aug 08, 2013 8:48 am 

Joined: Mon Aug 23, 2004 2:14 pm
Posts: 457
Location: Essex, Connecticut, USA
Greetings:
The diameter referred to in 49CFR Part 230.98 (6) & (7) is the journal diameter, not the wheel seat diameter or the axle shaft diameter.
The axle shaft diameter is almost always smaller than the journal or wheel seat.
Take a look at an AAR manual or a Locomotive Cyclopedia (1941 edition, page 686 Fig. 8.164) to see what a new axle looks like.
J.David


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 Post subject: Re: Driving Axle Diameter
PostPosted: Thu Aug 08, 2013 11:12 am 

Joined: Wed Oct 13, 2004 12:56 am
Posts: 341
Location: Northern California
The as forged surface of an axle makes the use of most non destructive testing methods difficult or impossible. Magnaflux or forms of dye penetrant were available for use on axles in the 1930s or earlier. I do not know how often steam locomotive axles were changed, since the removable tire would reduce the number of times the wheels were pressed on and off. The as forged axle surface was not permitted in freight car service, for new axes, when I went to work for the ail roads in the 1970s. But as far as I know the axles with as forges surfaces, known as black collar axles, were never outlawed. They were not allowed to be used on passenger cars. The fully machined axle has been in common use on electric railway equipment and diesel locomotives for a long time due to the need for the traction motor bearing seats between the wheels. Oscar Horger, VP of engineering at Timken, developed the raised wheel seat axle to reduce fatigue failures in axles in the late 1930s. It was always a fully machined axle.

I do not liked the FRA's use of three quarter inch as a condemning limit for the reduction in journal diameter. This results in stress levels in the axle, due to under size journals, to get much higher in smaller axles. I wounded if industry practices were different that the legal limit?


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 Post subject: Re: Driving Axle Diameter
PostPosted: Fri Aug 09, 2013 8:43 am 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 1235
Location: Strasburg, PA
Jim Baker wrote:
I'm looking at a 1929 ALCO 2-8-2T for possible restoration. How do I know what the original journal diameter was?


Here is information from ALCO Standard Practice on what the overall sizes their driving boxes were. Standard practice or not, the actual sizes and proportions of the boxes for various engines didn't necessarily follow these dimensions, but they will give you a general guide.

Baldwin standardized on making the distance between the box shoulders under the crown brass equal to the journal diameter plus ¼”. Not sure about ALCO.


Attachments:
ALCO std. practice.jpg
ALCO std. practice.jpg [ 339.06 KiB | Viewed 2112 times ]
BLW general design.jpg
BLW general design.jpg [ 341.92 KiB | Viewed 2112 times ]

_________________
"It was not easy to convince Allnutt. All his shop training had given him a profound prejudice against inexact work, experimental work, hit-or-miss work."
C. S. Forester

Strasburg Rail Road Mechanical Department
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 Post subject: Re: Driving Axle Diameter
PostPosted: Fri Aug 09, 2013 5:24 pm 

Joined: Fri Jul 23, 2010 12:41 pm
Posts: 377
Location: Minneapolis, MN
Thanks, Kelly! That is very important information when doing a rebuild. However, it does not answer the question regarding the ORIGINAL, as built journal diameter. Is there an ALCO standard practice for that dimension?


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 Post subject: Re: Driving Axle Diameter
PostPosted: Sat Aug 10, 2013 10:48 am 

Joined: Sat Apr 23, 2011 12:49 pm
Posts: 13
I believe you can find the original axle diameter by measuring up the driving box and using the table to find which axle size goes with your box dimensions (or which of the standard box dimensions are close to the dimensions of the worn box)


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 Post subject: Re: Driving Axle Diameter
PostPosted: Mon Aug 12, 2013 12:53 pm 

Joined: Fri Jul 23, 2010 12:41 pm
Posts: 377
Location: Minneapolis, MN
Original driving journal diameters are often found on locomotive erecting cards. This document is pretty valuable to any owner/operator and is often the only surviving drawing available to guide a restoration. For the Saginaw Timber No. 2 the erecting card was the only original drawing of the locomotive the owner was able to find.


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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 14, 2013 12:57 am 

Joined: Sat Apr 15, 2006 9:55 pm
Posts: 252
Location: San Diego area
Gentlemen: Thank you all for your help. I must apologize for not making my original request for information a bit clearer. I was attempting to keep it short. Here’s the long version.

I have the good fortune of having a nearly complete set of the original ALCO parts drawings for my locomotive. I am missing only 4 sheets out of 557.

I’ve attached a copy of the axle drawing. According to the “card record,” dimension “J” on the #1 and #4 axles is 8 inches; on the #2 and #3 axles it is 8 1/4 inches. What made me think that these might not be the original axles is the fact that “J” didn’t measure to what the drawing calls for. #s 1 and 4 measured 8 1/16 and an even 8 inches, respectively. Those are pretty close. But #’s 2 and 3 measured 8 1/16 and 8 13/16 respectively. So, #2 is 3/16 smaller than spec, and #3 is almost ½ inch larger.

So, what kind of tolerances did they have in 1929? I can see that the center section of the axle probably isn’t critical.

According to the drawing, the axle is the “J” diameter until only ½" before the journal, where it has a radius out to 8 ½ inches. On my axles, about 2" before the journals, the axle is gradually turned down to the approximate diameter of the journals. Would this be something done later when the journals had worn down?

I measured the journals just inboard of the crown brasses, getting diameters of 7 5/8, 8, 8 1/4 and 8 1/8 inches for #’s 1 thru 4 respectively. If these are the original axles, then #1 appears to be worn too far. But, are these the original axles?

The only things that look like dates are on the crank pins of the main (#3) drivers. Stamped on them is the following:

ALCO
2/40
7161-7044
71321
CAR-S

Is the 2/40 a date? Did the lumber company buy new crank pins from ALCO in 1940? Maybe ALCO, or someone else worked on the entire wheel sets in 1940? Got any guesses?

Thanks again.


Attachments:
Coos Axle Dwg Invert_1.jpg
Coos Axle Dwg Invert_1.jpg [ 79.8 KiB | Viewed 1655 times ]
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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 14, 2013 2:06 am 

Joined: Fri Jul 23, 2010 12:41 pm
Posts: 377
Location: Minneapolis, MN
If the drawing you posted is the correct one for your locomotive, then the original JOURNAL diameters are those specified (8-1/2 inches) for the new axle. Dimension "J" is not important as it never changes. The ONLY dimension that changes over time on the axle is the JOURNAL diameter. The journals can be turned and refinished as many times as neccessary UNTIL they are 3/4 inch undersize, at which point a new axle is required. In your case, the condemning limit for your JOURNALS is 7-3/4 inches. Please be aware that NONE of the journals on your locomotive will be the same diameter, even on the same axle. Some of the journals may be close to new and others close to condemning.

On the other hand, the outermost portion of the axle, the "Wheel Fit", is never changed because the wheels are almost never removed from the axle. If a new wheel is required, the axle is only machined if the wheel fit area has been damaged in some way. The new wheel is bored slightly undersize to provide the proper interference fit when it is pressed onto the axle.

When in use, these journal surfaces do wear and can get out of round, scored or tapered. When these conditions are encountered beyond a certain tolerance, the journals are turned and refinished and the driving boxes and brasses are machined or otherwise renewed to fit the smaller diameter journal.

Once a locomotive left the manufacturer, all maintenance and repair was usually the responsibility of the railroad. Locomotives almost NEVER returned to the manufacturer except for major modifications beyond the capability of the railroad's own shops. Sometimes new parts were purchased from the original manufacturer, but this was usually dependent on the capabilities of the railroad shops. All routine and heavy maintenance, including axle and crank pin replacement was done by the railroad's own shop forces.


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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 14, 2013 2:56 am 

Joined: Wed Oct 13, 2004 12:56 am
Posts: 341
Location: Northern California
How do you explain the 8 13/16" diameter journal? Maybe a replacement oversize axle to reuse existing drivers?


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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 14, 2013 7:09 am 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5250
Location: southeastern USA
From the other side of the country without any more information than what's been posted, it seems very likely to me that during the course of service on a logging railroad, probably toowards the end of tis career, a repair was made using an old axle from a larger locomotive that had been scrapped or stored unserviceable but was there and available, so........being a logging line in its last days, it got recycled. This is not uncommon.....what would be unlikely is having all the original parts still in one locomotive after a couple decades of industrial or shortline service.

These were tools to move stuff, and were expected to be used up, patched together, and discarded what the cost of extensive patching grew too high.

dave

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 Post subject: Re: Driving Axle Diameter
PostPosted: Wed Aug 14, 2013 8:19 am 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 1235
Location: Strasburg, PA
Jim Baker wrote:
I have the good fortune of having a nearly complete set of the original ALCO parts drawings for my locomotive. I am missing only 4 sheets out of 557.

Good for you! Having a complete set of blueprints is huge. If you haven't already done so, I would advise taking the whole stack to a large format copy shop and have them digitalized. It’s cheaper than having paper copies made, and then you can keep a disc safe, and print out disposable copies as needed.

Quote:
So, what kind of tolerances did they have in 1929? I can see that the center section of the axle probably isn’t critical.

Even though it isn’t critical, the original axles would have followed the blueprints within spring caliper tolerance, perhaps within 1/32” or so. I’d say that every axle where dimension “J” is materially different than the blueprint is sure to be a replacement axle.

Quote:
According to the drawing, the axle is the “J” diameter until only ½" before the journal, where it has a radius out to 8 ½ inches. On my axles, about 2" before the journals, the axle is gradually turned down to the approximate diameter of the journals. Would this be something done later when the journals had worn down?

It is common when turning down journals beyond the point that the journal is smaller than diameter “J”, to let the journal diameter run out into the center section of the axle to have that shoulder to the now larger center section well away from the end of the crown brass.

Quote:
I measured the journals just inboard of the crown brasses, getting diameters of 7 5/8, 8, 8 1/4 and 8 1/8 inches for #’s 1 thru 4 respectively. If these are the original axles, then #1 appears to be worn too far. But, are these the original axles?

Original axle or not, thanks to your blueprints, 8-1/2” is the original size for this engine, and is the dimension that needs to be stamped into the axle ends. So yes, the axle with the journal diameter of 7-5/8” will need to be replaced.

It is quite common for the main axle to be larger than the others to take the added stress. I see where you mentioned that the #2 and #3 axles had a larger center section according to the card. Be sure that all four axles had the same new journal diameter before you stamp the axle ends. Larger journals on the main axle would also mean larger driving boxes on that axle, easy to spot.

It’s hard to say anything intelligent about the stamping you found in the crankpins. As Dave said, it’s quite likely that they have been replaced in the locomotive’s life time, and it’s possible that the stamping you found is left over from the crankpin’s previous life as a larger crankpin of some larger engine.

_________________
"It was not easy to convince Allnutt. All his shop training had given him a profound prejudice against inexact work, experimental work, hit-or-miss work."
C. S. Forester

Strasburg Rail Road Mechanical Department


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