Roller Bearings in steam Locomotives

[BR60103]

I have wondered for a number of years now: Why didn't the railroads go for more roller bearings on the big steamers?
Can anyone give details about the following:
How much more efficient would a roller bearing be?
How much did they cost?
What would it take to replace plain bearing with rollers? Could they be fitted in the same openings in the frame or would something have to be cut and carved? Could the be fitted around existing axles or would the wheels have to come off first?
Which of the currently running locos have roller bearings?

[Anonymous]

Can't answer most of your questions, but I used to be w/ PL&RHS(Pueblo, CO) which owns/is restoring ATSF 2912. It was built in 1944 and has roller brgs. When it was first moved to its current location, after nearly 50 years of outside/display storge, oil leaked from the rod bearings and it had to be "held back" so it would not roll too far or too fast!

[CSSHEGEWISCH]

Timken showed the efficiency of roller bearings with its demonstrator 4-8-4 #1111. I don't remember the figures but an appreciable amount more freight could be moved on the same amount of coal.
Railroads have historically been conservative organizations so the slow adaptation of roller bearings on steam locomotives may have been affected by that factor. In a similar vein, some of the earlier diesels were equipped with friction bearings, including some GP7's on BRC.

[Anonymous]

While we are on the subject of bearings, are friction bearings on railroad frieght cars allowed any more?? If not, what year were they outlawed?? I know CSX will not allow them on there rails.
TIM A

[Anonymous]

When we were rebuilding the the ex Reading 2100 in St.Thomas ON we
were talking to Timken and we were looking at a price of 150,000 to 200,000
to change over to roller bearings.

On the subject of friction bearings on cars there was alot of maintenance
involved with the up keep of friction bearings.
Some railways still use cars that have Friction bearings but they can use it only on there own lines.
These type of bearings are prone to give you hot box problems because of
lack of oil,and could cause a derailment.
So the AAR and the #1's decided to get rid of plain bearing wheels.
Also the railways saved alot of money from the parts they did not have to have on
hand and saved bigger bucks on the staff they could lay off who oiled and repaired these cars.

[Anonymous]

Out of their entire fleet , the SP had only 2 roller bearing steamers. They were GS-5's # 4458 and 4459 which are no longer running. The only reason they were designated GS-5 was because of the bearings. The 4449 has roller bearings on its lead truck only.

[Anonymous]

Do steam engines require a spiecial oil for lubricating because of the heat?? I would think it would have to be a thick oil, almost crude in nature.
TIM A

[Anonymous]

Tim . All i know is that Doyle McCormack of the 4449 fame has custom made rod pin grease. They also have a new type of lube pad and oil for the friction brgs..

[kenneo]

One of the reasons for not going to rollers early on is that, roller bearings, when parked supporting heavy equipment, can develope flat spots on individual rollers and will then have a catastrophic failure (hot box) within 5 track miles. Friction bearings wont do that because the contact areas between the bearing surfaces is much larger than that of roller bearings. And that contact area difference is the major reason for roller bearings operating better and cheaper.

If you are storing heavy equipment that operates on roller bearings, you need to move the car/locomotive at least once a week and be sure that you don't park it back on the spot (bearing spot, that is) it was on before you moved it.

Just to confuse the issue, not all bearings are like this. Locomotive bearings used since the early '50's don't get storage caused flat spots. But our rotories sure did. It was not a fun thing to explain how come the rotory snow plow developed a hot box and blocked the whole mountain for five hours (or more) while the rip track came out to change the axel. Seemed like it would always get a UPS pig, a passenger train and be in the middle of a blizzard.

[Anonymous]

I am no expert but I suspect that World War Two may have had a major impact on why roller Bearings were not more universal. The war productions board pretty much restricted locomotive designs to what was then in use and proven to be effective.
I know board wasn't happy with SP building the GS6's but the OK'd it but then took tw of those engines and sent them to the Western Pacific Railroad. I wish I had seen them in regular service. wc

[Anonymous]

the NYC niagaras were equiped with roller bearings, i believe both on all axles and on the rods. i remember seeing news photos of some beauty queens pulling one. al

[Overmod]

Rollers were considerably more expensive than plain bearings for most engine applications, and required special handling -- for example, consider what needs to be done to install one on a driver axle, compared to machining a journal on the same axle. They were also aftermarket parts supplied by specialty companies (Timken, SKF, Fafnir, etc.) and, in an age where first-cost cheapness was a major locomotive selling point, cost a great deal of unavoidable-profit money up front. Which, in turn, probably means that at least some of the claims for rollers on steam locomotives MIGHT have marketing, rather than engineering, origin...

A big problem is that roller bearings of the '40s and '50s could not tolerate very much misalignment, either transient or permanent. That is one of the principal reasons imho for the use of the very heavy and expensive GSC-style cast-steel one-piece underframes, and for the invention of effective self-adjusting axlebox wedges. To provide the larger space for roller axleboxes without compromising frame flexing in any plane is difficult. Note also the arrangements that have to be made to permit lateral motion of a driver axle with rollers. Note also the arrangements with roller bearings in rods and motionwork, sometimes involving fun things like spherical-bearing outer shells in rod bearings to permit lateral axle motion. There are some valve-gear parts which see very large lateral stresses during some parts of operation (cf. the ultimate cause of valve-gear failure on the N&W 4-8-4 tested on the Altoona test plant), and to equip these with rollers involves much more robust components, sometimes involving multiple-row bearings on either side of a rod or member.

A point often missed about this is that, as engines became older and often less 'desirable', the necessary precision and care their roller bearings required were less and less devoted to them. My guess is that this was a significant factor in the early retirement of roller-bearing classes in a great many cases, but that it would be difficult if not impossible to distingui***his cause from others, including relative size and complexity of engines remaining in service.

In some cases, roller bearings could be substituted for plain ones in existing frames, but in general they required much greater dimensions all around the axle -- since all the elements of the bearing either rotate or have to support rotating members, they cannot be made 'thinner' in the ways a plain bearing can for the same effective load capacity. The problem becomes even more extreme if the bearing has to be 'split', with the cage and outer race in more than one piece, assembled with external bolted caps.

There is also a certain amount of 'fun' involved with adjusting out 'play' in the bearings as they wear. In a double-taper design this involves moving one set of races slightly relative to the other, and at least one company (SKF) now has a line of roller bearings that has been specially designed to make this very fine adjustment easily. I would be interested to read comments from people with distinctive experience in maintaining these bearings (Steve Lee? Anyone from VMT who worked on 611?)

The problem of flats and out-of-round deformation has almost entirely been solved with better alloys and manufacturing -- but most of that came long after the effective end of steam. Likewise, there have been very great increases in 'sealed' service life of bearings, to the extent that they easily outlast the wheels attached to their axle in both freight-car and locomotive service!

Something that has been repeatedly mentioned in the contemporary literature on railroad use of roller bearings since at least 1927 (date of the first technical reference I have located) is that the friction advantage of a roller bearing is almost all related to starting and slow-speed resistance (e.g. with cold oil between journal and brass), not higher-speed operation. Indeed, the move toward installing roller bearings on freight cars in interchange service was retarded somewhat by the introduction of polymer lubricating pads, etc. that reduced hotbox problems. I believe the 'real' principal reason for eliminating plain bearings in interchange service is that they *do* require periodic skilled attention to their lube levels, without which they might run dry, while modern rollers can almost always dispense with that kind of attention.

Even on steam locomotives, most of the bearings didn't see excessive 'heat'. The one exception was on the trailing truck, where the ashpan and grate are in fairly close proximity to the bearings, but even there I don't think the exposure would be particularly severe on a well-designed locomotive. I don't think any steam-locomotive roller bearing, whether on axles or in motionwork, used a particularly thick lubricant anyway -- certainly not something thick and metallic-loaded like Alemite! -- and the lubricant would *never* have characteristics like 'crude oil'. Remember that the bearing itself takes the load, not the 'lubricosity' of the oil film, and the lubricant is serving other purposes (such as keeping any 'scrub' or worn-taper problems from wearing metal-to-metal contact points through the hardened surface of the rollers!) Again, I don't know offhand how many locomotives with rollers used a common lubrication system with a 'drip' or hydrostatic lubricator for plain bearings -- but there are people who do know and can answer.

I might also mention that there are people still living who have firsthand experience with use of roller bearings vs. plain on different locomotives and parts -- and who would probably be delighted to give information...

[dknelson]

There were many technological improvements, from better stacks to better valve gear, that could have been made to American steam but weren't. part of the reason was the Great Depression which was a big damper on new locomotive construction for many years - picking up about the time when the more forward thinking types realized the handwriting was on the wall for steam. And it is interesting to note how many early diesels also had friction trucks
But there were roller bearing equipped steam locomotives in the later years.
Dave Nelson

[Anonymous]

I don't quite rember the exact month but I know it was the new 20th Century Limited in the Chicago rail yards that the entire train was pulled by muscle man Charles Atlas to show the ease of roller bearings. The year was 1948 and I think the picture was in Trains magazine
*** Reitmeyer

[BR60103]

Thanks to everyone who replied. You seem to have covered all my questions.

[Anonymous]

Overmod, You have been very helpful.
TIM A