Hello,
what is the difference between friction and roller bearing trucks as mentioned about the ho boston and maine gp-9 by athearn genesis. I guess it might passenger or freight usage or new technology during the 1950’s. Thanks for any advice.
Regards Matthew Redden
I’m not familiar with those models, but friction bearing trucks required periodic lubrication, so the bearings were easily accessible within their journal boxes. Roller bearings are sealed units, and require no additional lubrication during normal use, so there’s no easy access required.
Roller bearings wouldn’t necessarily indicate passenger service - a more likely indicator of such would be a loco equipped with a steam generator.
Roller bearings had been in use by railroads (though not especially common) since the '20s, so they were hardly new technology by the '50s. [swg]
Wayne
Matthew
To answer your question in very basic terms, friction bearings consist of an outer bearing surface (the race) into which is inserted a slightly smaller shaft. The outer bearing is stationary. The shaft rotates within the outer bearing. Frequent lubrication is required to keep the bearing surfaces from grinding into each other.
A roller bearing has a set of small cylindrical rollers which are located between the outer bearing surface and the inner shaft. As the shaft rotates, the rollers ‘roll’ around the shaft thereby (almost) eliminating the friction between the race and the shaft. Provided that their seals work to keep them dry they will run for a very long time without maintenance.
One of the primary reasons for cabooses was to allow the conductor to watch for signs of the friction bearings failing. They would usually produce a shower of sparks when they failed.
Dave
P.S. Maybe one of the manufacturers of electronic simulators (i.e. arc welders) can come up with a simulator for a bad wheel bearing. That would be a neat addition to an operating session!
go to google images and look at railroad friction bearings. then, look at roller bearings. a picture is worth a thousand words.
friction bearings were babit coated brass riding on the polished journals at the ends of the axles. they were outlawed in interchange service quite a few years back.
diesel locomotives with friction bearings were mostly those that operated a slower speeds like in yard or terminal transfer service. the PRR acquired a few used electric locomotives with friction bearings and tried them in helper service, mostly west out of Philly and the friction bearings overheated so badly they were a problem when assigned to fast trains or subjected to prolonged high speed running.
friction bearings have been giving railroads a headache for many years. some steam locomotives had water hoses hanging down from the sides of their tenders that dripped water into the journal boxes to cool the bearings when needed. this was not a normal condition but served as a quick fix out on the road.
Charlie
There are more or less two type of bearing used on trains, plain bearings (often called “friction” bearings) and roller bearings.
Plain bearings were generally used on freight cars up through the 1950’s, then roller bearings were phased in over the next 3 decades and now only roller bearings are used in interchange service.
On a truck with plain bearings there is a “journal box” around the end of each axle. The journal box can be a separate piece (arch bar and Andrews trucks) or part of the sideframe on cast sideframe trucks. In the top of the journal box there is a receiver built that holds a bearing block, a large piece of brass about 8" square and about 3" thick that has a curved surface on the bottom that fits on the top of the axle end. The bearing block is known as the “brass”. The axle end is a smooth, cylinder, not tapered like on a model axle. Underneath the axle end in the journal box is a space for lubricant and wicking. Cotton waste (looks like pillow stuffing) or cotton pads are put in the bottom of the journal box along with oil. The cotton wicks the oil up to the axle and the turning axle wipes it on the bottom of the brass lubricating it. There is a seal in the back of the journal box where the axle passes through the back of the journal box. On the front top of the journal box is a lid that can be opened to allow cotton waste and oil to be added and the axle end to be inspected.
If the journal runs low or out of oil or the wicking doesn’t touch the axle, the bearing will run dry and the friction will heat up the bearing to the point the oil and packing will catch fire. If the bearing continues to operate it will become hot enough to start melting the axle end and wearing into the metal. Eventually the axle end burns off, leaving a cone shaped stub on the end of the axle. That allows the side frame to drop and hit the grou
The differences in bearing types have been fairly well covered in this thread, so I figured I’ll just add a note or two.
Roller bearings for railcars were available by the 1920s if not earlier (after all, automobiles used them), and while a great improvement over friction journal bearings, the big reason the US railroads didn’t universally adopted them for freight cars until required to was, of course, cost - a great book from the 1940s (which I thought for sure was “Railroading In the United States”, but Google says no way - alas, our local library sold off its only copy before I even knew I could have purchased it) talked about giving freight cars “wings” with roller bearing, and then gave the economic reasons why railroads did not find it cost beneficial to adopt on their own volition.
Here’s an article from Time magazine, 1941 about that line of thought which may be of interest: Railroads: Very Bad Taste, which I now see is behind a paywall. Well, luckily years ago, I posted some snippets of the article
[quote]
Roller bearings, said Timken’s intrepid ad, would permit “one-speed” railroading (identical speeds for freight and passenger trains), would accelerate the whole defense program, save building many new cars. Other roller-bearing claims: 1) starting resistance reduced by 88%; 2) elimination of hotbox delay; 3) reduced maintenance costs.
…
During all that time Sanders has had one passionate reverie: all U.S. railroad equipment on roller bearings—preferably Timken. His first break came in 1926 when the Milwaukee put roller bearings under its passenger trains. Now scores of U.S. streamliners, hundreds of crack passenger trains roll on rollers. But the whole U.S. coach and Pullman market is only 39,000 cars.
…
So Sanders went after the U.S. railroads’ 1,750,000 freight cars. Results: practically zero. Railroad men thought roller bearin
If you are thinking of the Roundhouse Products convertible Bettendorf trucks, friction or roller bearing, here’s your chance to get a pair: http://www.ebay.com/itm/2-PAIR-ROUNDHOUSE-HO-Scale-CONVERTIBLE-BETTENDORF-TRUCKS-NEW-/180928491225
Package I have says $4.95 on it. For some reason there is no part number on the package.
Quick visual check for friction (originally anti-friction, when they were introduced about 19 decades ago) bearings on a model truck: The journal box front slopes outward from top to bottom and has a rectangular cover. If the old brass has been traded in for a roller bearing the cover will be missing. If built with roller bearings the journal enclosure will have a vertical front, sometimes including a rotating cap (turns with the axle.)
Roller bearings ARE lubricated - with heavy grease, like the wheel bearings on your car. Friction bearing oil was much less viscous.
I have a few `new in 1964’ cars with the JNR’s version of high speed (120kph) roller bearings. The journal enclosures are HUGE!
Chuck (Modeling Central Japan in September, 1964)
Looking through my stash of unbuilt stuff, I find that Eastern Car Works also offered Bettendorf conversion trucks. That kit part number is 9056. No picture, but they were Walthers 117-9056: http://www.walthers.com/exec/productinfo/117-9056
Deshusmans reply was superb and very accurate.
As an retired wheel shop foreman we were still reconditioning plain bearing axles during the 70s and 80s, however roller bearing axles were becoming more dominant as the friction type became ot of tolerance from several recondition process’s over its life time.
During WW ll when a friction bearing surface became heated and had a slight bluish discoloration it was reconditioned and stamped with a 1/2 large RJ on both ends ( end are called the Buttons)of the axle. Thereby not hurting the war effort as these RJs would be pulled out of service after the war. Before the war any heat discoloration (or ever touching a wheel or axle with a flame of a torch it was automatically scraped) However these axles were still coming into our wheel repair shops into the 80s.
Friction bearing axles after qualifying to numerous tolerances, were turned to a 125 or under micro-inch finish, and then rolled with stellite rollers compressing the axle finish to a glass-like 4 micro-inch finish. This was called burnishing
There were three main manufacturer’s of roller bearings, Timken, Hyall, and SKF. In the 70s a Japanese roller bearing manufacture ( I think the brand was NSK, but my recall is fading LOL) sold SP this bearing with a ten year warranty, a far better warranty then American brands. These were put on in place of other brands by the box car loads. Other brands of bearings were stored if these Japanese bearing were available.
Being that each bearing has an inner race with tapered roller bearings mounted in a cage, of course this was for separation and the keeping the load distributed to the majority of the top bearings of which Carry the loaded car weight… The Japanese added one extra roller bearing to the cage, after some time our quality control people found that these bearing assemblies to be over engineered and t
I tried to read carefully all posts but did not see the classic term for a smoking or flaming journal box.
The folks in the cupola of the caboose would look for smoke rising from alongside the train and order a stop for a “hot box”. Oil was rarely used in its normal state but more often a thick or thinned oily grease was slopped into the open journal boxes using a wooden paddle and cloth from a bucket to supply lubrication when out on the road. The wadding absorbed this and the normal frictional heat in rolling journal box and bearing worked to liquify the greasy mixture and get it into the journal bearing area.
Journal box covers were often opened by a deft, trained foot using the toe portion placed under the box cover bottom lip. They were similarly closed by a push down on the cover by the foot as well.
Inspite of all best efforts, an occasional journal box would go dry or not have enough lubricant to make a specific trip. The bearing would get hot enough to melt the bearing’s babbit and then the bearing base metal would rub against tne steel axle and then it was only a short time before what remaining grease and oil on the wading would first smoke and then catch fire in some cases.
With 4 journal boxes per truck and two trucks per car, a 70 car long haul train had 560 journal boxes that could catch fire or develop issues. It only took one.
With modern non-servicable roller bearings and no cabooses, a failure, (rare), will almost always lead to a derailment. Same result as an un-attended “hot box” only less frequent and no one watching for trouble.
Richard Hull
The term “Hot Box?” Dehusman had it covered in his post of 20 July 2012, and even gave a description of what happens, although his hot box failure ended with the axle end shearing off and the axle dropping out of the truck.
Ctrl+F Find/Search works well in IE8, should be the same or similar function in Chrome & Firefox.
OF all the mechanical bearing demands of today. friction… Babbitt… bearings only seem to remain in the automotive engine. There are whole schools of machinists who deal with automotive bearings and not much is commingled. Most machinists will beg off in a conversation about how auto engines get anything done vs the rest of the world.
Babbitt is a soft lead - tin alloy that is porous and can hold a lot of oil in that porosity. In later years nickle has been added to the alloy for speed and durability. With the weights dealt with in railroads… Babbitt bearings are rather unforgiving. In a auto engine they can survive a lot of insults.
Lubricants were not then what they are today… If they had then the lubricant capabilities that we enjoy today… a lot more machinery would have survived and still be in service.
see ya
Bob
Did some more checking and in Norwood’s, “Narrow Gauge Remberances”, he gives a narrow gauge dictionary of sorts. The hot box was also called a “blazer” or a “stinker” on the railroad. If a work crew member, section man or other railroad personnel saw a hot box or heard axle squeal from a passing train, they would signal the caboose crew as they passed by holding their nose and pointing down and the rails to alert them.
I guess sometimes the smoker/blazer phase had passed un-noticed and a horrid squeal could only be signaled from personnel on the ground as a train passed by.
Interestingly, last week while at a grade crossing on my way home from work one car went by on a long train with a horrible thump…thump…thump, denoting that a wheel had a flat spot on it, having been dragged, locked up, sometime in the past. With all the rolling stuff on trains and the tonnage hauled, there can be a lot of issues pop up due to normal wear and tear.
Richard
I think Scott Whitney explained on the Yahoo BM_RR group that the B&M GP9 s were delivered with an early style on a Roller Bearing ,these at first look appeared similar to Friction Bearing boxes. .As the years went by some may have been replaced by the newer style Roller Bearing. It seems like Athearn in error is calling them Friction Bearing.
If its ok I am going to post Scotts reply from BM_RR Yahoo group
Re: [BM_RR] Atearn GP-9
You are correct that B&M units all rode on the early version of roller
bearing boxes and I’d like to know who the clown is that keeps calling them
friction bearings! The reason for this is the same old story of how EMD
allowed tradeins of locomotives. Simply stated, if the unit being traded in
had ANY components that could be overhauled and used in the construction of
new units purchased on the trade-in plan, they got those components.
NO, they were NOT the actual components from trade-ins except for luck of
the draw. The old components went onto a vast pool, were simply picked from
that pile, overhauled, and then placed back on the shelf for re-use. B&M FT
boxes could have would up under later B&M units or anybody elses but early
B&M GP-9 units did NOT get FT parts from the B&M.
The above explains why the B&M GP-9’s and 18’s were delivered on older
roller bearing boxes when the newer style was already in production. You
get back what you traded in and the inventory was strictly monitored. This
explains why B&M GP-18’s all had 36" cooling fans except for 1755. B&M had
run out of trade-in units so it received the then standard 48" fans instead.
The 36" fans were a peculiar spotting feature that most B&M fans simply took
for granted.
SJW
.
friction barring trucks used steel boxes on the outside of the trucks to house oil and the barrings. the problem with thee trucks is they overheated (hence the name HOTBOX!) by 1972 all of these were replaced with AAR Roller Trucks. Roller Trucks use steel balls on each axle and each is housed on a plate welded to the end of the axle and runs in a race ring which is also welded onto the plate. the balls roll around as the axle is turning to lubricate the barring and the axle the only time they need to be changed is when a wheel starts spalling this is the tell tell sign that the wheel and axle need to be replaced.
They were in service way longer than that. In late 1980 I worken on a burnt off journal on a plain bearing boxcar just south of Durand, KS. It was a unit train of 40 ft boxcars of grain for Mexico. When the journal dropped the wheel hit the wood floor of the boxcar and broke it, letting grain pour out of the car all over the truck. We had to dig through the corn to get to the journal. We knew we were getting close when we hit popcorn.
Actually they use cylindrical or tapered “rollers” not balls, why the name of the bearing is a “roller bearing” instead of a “ball bearing”.
Thank you, Dehusman, for correctly pointing out that the things that are often called “friction bearings” are more accurately called “plain bearings.” I’ve been told that the “friction bearing” term was created by Timken in an ad campaign intended to disparage plain bearings by claiming (rightly or wrongly) that their inherent design involved more friction.
Tom
A vintage film that shows a hot box. Begins about 15 mins 30 secs in.
https://www.youtube.com/watch?v=4JensPwtu4s
Jeff
they were phased out by the 80s when the railroads replaced the caboose with the FRED Beacon but 1972 was when they made the switch.