As for the PRR stoker (and power reverse) subjects, if I recall they were made to install them after a certain date. PRR didn't believe in making life easy until they finally built something big enough where it couldn't be hand fired. I don't remember where I heard this, possibly from my Dad years ago.
It will be interesting to see how the No. 4 axle cellars work now. In spite of what anyone says, I don't think the block grease is fit for anything other than pin grease any more. A lost art. I've heard that it's too dangerous to make and other stories, but wonder if it's just the lack of demand that keeps something like Texaco HY-TEX 8 from showing up nowadays.
Did you do anything different with the crown brass grooves on the axle now that it's oil fed? I suppose it would be possible to put fittings on the box and use a lubricator.
As I said many times in my 1522 days, it's too bad it's so hard and outrageously expensive to conver the driving axles to roller bearings. We did all the rest on the engine and tender.

One should not forget that W.W. Atterbury (PRR President 1925 - 1935) was politically active and frequently in conflict with labor. As much as we admire the accomplishments of the PRR, I suspect their low opinion of labor contributed to a harsh work environment in the cab (i.e. reluctance to fit stokers).

When making the change from block grease to oil one must put a layer of tin on the brass surface of an appropriate thickness. So, the "grease grooves" go away entirely once the tin is applied.

Just wait a little while longer on the "as good as the old stuff" grease. I am getting very close to having everything set up for a new to the industry product.

Cheers, Jason

Tin? or Babbitt? IIRC, SP 4449 had oil cellars and babbitted brasses but when one of the cellars cracked (on the World's Fair Daylight to New Orleans?), they wound up running it on grease, with the babbitt wearing down to the original brass. Not sure if that box was ever restored back to oil lubrication.

Michael Seitz
Missoula MT

I keep hearing about this “requirement” for oil cellars. This may be one to send into “Myth Busters”. After a quick count, I come up with seventy six (not bad for before breakfast on a Sunday morning) driving boxes with oil cellars that I have been involved in the operation of, and still more that I have built or overhauled, and I have yet to come across one that had or needed a Babbitt or tin liner on the crown brass.

What is a requirement is a crown brass made of the proper bronze (and not filled with sand) that is a proper fit to the journal and box, a journal that is in decent condition, without heat checks, and a pad that can be counted on to reliably supply oil. When those requirements are met, the boxes run at ambient temperature, plus five or ten degrees at most. In my experience, any oil lubricated box that runs hot has one of the problems above as a cause.

In the rare instances where old specs called for lined crown brasses (such as on the Daylight), I suspect that as much as anything an acknowledgement on the railroad’s part as to just how crappy and contaminated their bronze sand castings were, and that they couldn’t be trusted not to expose a sand pocket in the middle of a high speed run.

Some railroads used absolutely pure tin on crosshead shoes versus traditional "babbit", which does of course contain tin. Likewise, the "babbit" used on crown brasses ranges from from almost standard car brass composition (on smaller lokis) to pure tin on crown brasses. I suspect it comes down to a matter of economy/what will work at minimum in service as tin was proven to be a superior performer.

There is one product in particular available today which provides excellent service.

Kelly,

What about the SY boxes you did for the valley? While not entirely lined you re-poured the rather HUGE babbit "pads" which comprised a vast majority of the load bearing surface. Of these engines you have worked on, how many have axle loadings over 48,000lb-68,975lb which operate in"real" service at speeds in in excess of 40-70mph respectively?
I have seen/worked on a notable number of oil lubed engines as well and I will say that all SMALL/LOW SPEED/LOW AXLE LOADING locomotives (small mikes, small consolidations on down to 0-4-0s) I have seen (save two) have no babbit/tin......whatever. Nor have I every seen a spec for lining the bearings of lokis such as these. However, the specs exist for larger locomotives...... I tend to suspect it is e requirement brought on by crossing a certain service condition threshold.

Cheers, Jason

[quote="J3a-614"]Here's some material on the 4501, including some specifications, but an important one is missing--grate area:

http://hawkinsrails.net/steam/4501/sr_4501.htm

The firebox on the 4501 is 54 square feet. This comes from the book Locomotive 4501 by David P. Morgan.

An interesting babbitt alloy is "XXXX Nickel Babbitt" which can handle much higher specific loading than plain babbitt. There is a main crankpin bearing of this material on a 700 HP steam engine generator which has now run 40,000 hours and still looks great. The engine formerly had a problem with this bearing breaking up every 8000-16,000 hours over the last 60 years of its life. Later engines of this model were provided a wider crankpin and bearing which solved the design problem. But for this engine, the XXXX Nickel works well. Speaking with the guys who poured it (and many past bearings) there was no particular problems with pouring this material. Their practice (which stems from the OEM) does involve high preheat and thorough peening as the babbitt cools.

There’s a skeleton in every closet, forgot about the Valley. Never the less, I’d say they don’t count per your original statement of, “one must put a layer of tin on the brass surface of an appropriate thickness”, since I believe that the brass still is in contact with the journal between the pads. Your original blanket comment was the reason behind my initial post.

Regarding high axle loadings, it seems like the builders were quite standardized on a maximum bearing pressure of 180 PSI for crown brasses regardless of the size of the locomotive, so there would be no more reason to expect a heavy locomotive to run hot compared to a light one in a given service. The greater “embed-ability” of Babbitted crown brasses would be a advantage as far as its tolerance of grit in the bearing, I recall seeing an SP company film showing a 4-8-2 running through a sand storm. The sand was blowing though the spokes like snow as the engine rolled by. Perhaps they had conditions like that in mind when calling out Babbitted crown brasses.

Regarding very heavy oil cellar locomotives running at high speeds, other than #4449, are there any? Like it or not, all things considered, “SMALL/LOW SPEED/LOW AXLE LOADING locomotives (small mikes, small consolidations on down to 0-4-0s)” are the future of steam railroading in the US for the vast majority of operations. Costs being what they are, there is no advantage to adding complications that don’t create a clear benefit for the service intended.

PRR #7002, and for that matter all of the E6 Atlantics, has (had) a 55 square foot grate, and none of them ever had a stoker. #7002 wasn’t particularly hard to keep up with, including when making 60 per somewhere between Philadelphia and Harrisburg.

I recall a conversation with Doug Karhan (sorry if I butchered the spelling), where he mentioned that #4501 had a reputation as a hard engine to fire until one day while doing work on the front end in Birmingham, they discovered a hole in one of the steam pipes “that you could put a pencil through”. He said that once that hole was plugged, he thought she was a pretty free steamer.

Dumb question for all concerned regarding babbitted crown brasses: Wouldn't the presence of babbitt make it easier to rebuild a worn crown brass, by just replaceing the babbitt and remachining to suit? Also, wouldn't the babbitt be less prone to abrading the axle? Seems simpler/cheaper to replace babbitt than to remachine an entire new crown brass. Would suspect that, absent abrasive (desert) operating conditions, that brasses could operate longer between failures and take more abuse (wear) than babbitted crowns.

Yes and no in my admittedly limited experience. I gladly defer to Kelly and many others with more hands-on.

Babbit is used commonly in the UK where a form of it is called "white metal" and seems to require renewal at intervals that would discourage US operators. Remember, their runs are shorter and their axle loads much lighter than mainline US.

And, there is a wide variety of quality differences between babbit jobs - I've seen adhesion and inclusion problems in some lined bearings that failed in service on light car journal brasses, much less locomotive size. Pounding out of slightly loose rod brasses also......which good bronze bearing stuff would have just absorbed until the next convenient time to reset them.

Done properly and well designed, they should peform as expected since we know a lot about what to expect. The ability to correctly design and apply them in our context is probably not common any longer.

Sinclair Lewis wrote a book about it you might want to read.

dave

Alas, the Lewis book is about the stultifying social life of a middle class household in the American upper midwest in the 1910 era. It does have trains in it, but they are not the central theme, or even close to it.

Michael Seitz
Missoula MT

Reading and Northern 425's firebox is 54.2 square foot. It's not bad to fire with properly placed scoops.

Kelly,

Much to even my surprise, the SY prints call for 2mm of babbit to protrude from the surface of the crownbrass at the point it is machined for the axle diameter..... I wouldn't believe it if I had not seen the print(or photo of) with my own eyes.

While there are standards for bearing pressures (lima's being lower than the others), sense is made of considering the surface feet per minute of the axle journal when a locomotive such as the 630 is running at 40-50mph (NS track speed may be 40 but more than one individual has confirmed they have seen 50 on a GPS/Speedometer app). At an RPM of 285 (for 45mph) when coupled with the thrust and impact loadings experienced while a locomotive of this size is pulling an actual train (versus a caboose local with an 0-4-0 at 15mph or 132 rpm with drastically lower thrust and impact loadings) I would say and I think it is clearly evident that there are tangible differences.

I am (as well as everyone should be) aware that smaller than mainline steam is the future.....sadly. As I stated, the non-babbited bearings obviously work for the smaller low speed stuff. I am/have been referring specifically to locomotives such as the 4449 and now the 630.

Cheers Kelly, Jason