• Friction Bearing Trucks

  • General discussion about locomotives, rolling stock, and equipment
General discussion about locomotives, rolling stock, and equipment

Moderator: John_Perkowski

  by 2spot
Some railways use friction bearing truck equipped locomotives on a regular basis. Some class 1 roads wont move locomotives equipped this way dead-in-train. Maybe none do. Is there a hazard in friction bearings,and if so, why are they allowed on some roads and not others?
  by H.F.Malone
Correct terminology: "plain bearing" or "solid bearing".... all bearings are "friction" bearings, or more correctly, "anti-friction" bearings.

Anyway, back in the old days, the railroads had lots of yards, car inspectors, cabooses with multiple crewmembers, slow freight speeds (usually 50 mph or less), you get the picture. The plain bearing assembly is a maintenance-intensive item-- it needs to be oiled every few hundred miles, periodically repacked with the oil wick ("waste" used until about 1960, then the "journal pad" came along) cleaned or replaced every 36 months, the brass can get dislodged, etc. All in all, a lot of effort to keep 'em running right. There's no hazard, per se, but attention must be paid to the things, and when the yards, car knockers and cabooses went away, the ability to keep an eye on these old things did too. How many "old-timers" are still left on most railroads? Employees, that is.

Lots of ads in the 1950s RR trade press extolling the virtues of plain brgs, especially their lower first cost. Once Timken developed the AP ("all-purpose"-- and much less expensive) bearing about 1956, there was no looking back as more and more new freight cars were delivered on rollers.

Right from the start, 98% of road diesels, freight and passenger, rode on rollers. The slow-speed switchers stayed on plain brgs due to cost and speeds under 45-50 mph.

Plain bearings were prohibited on interchange revenue freight cars as of Jan. 1, 1994. There is NOT an "FRA ban" on them, but an AAR prohibition. A railroad can choose to move a properly service plain bearing with no FRA problems (for example, locomotives are not revenue freight cars!) but they have seized upon the 1994 interchange ban as an easy way to refuse to move "old, weird and historic" equipment.

You may have noticed that lineside hotbox detectors, originally developed in the late 50s to deal with plain brgs, are still used, and it is not unheard of for a roller bearing to fail, burn off the axle end, and cause a wreck or derailment (just one example: a NJ Transit MU train about 2-3 years ago). Would any railroad then say that roller bearings are inherently dangerous?

Properly serviced and lubricated, there is NO hazard to operation of plain bearings-- they DID work for almost 150 years, and at passenger train speeds (think 20th Century Ltd at 80+ mph!).

It's a skill kind of like firing a steam locomotive-- no Class 1 railroader would have a clue in 2004, but there are plenty of preservation railroaders who are real familiar with the things (steam locos and/or plain bearings)!!

  by 2spot
I often see these engines; switchers and small (old )road switchers for sale on Railswap and the like. I wondered what was up with the interchange restriction, and assumed it was a safety(or fire) risk. Your answer makes sense, H.F.Malone, Thank you.

  by Aji-tater
From an engineering point, "plain' bearings may be correct. Most railroaders I have heard use the term "friction" bearings, whether technically correct or not.

  by SRS125
I have seen to cabooses with friction bearing trucks get moved from one railroad to anouther back about 6 years ago on a short move of about 25 miles.

I do find it intresting to still see the old truck frames thow still being used. I saw one once thinking it was an orginal friction truck on an old NYS&W Ex CR/PC Ballest Hopper. The guy lifted the lid and pointed out to me that it was converted into a roller bearing but the truck on the outher end of the car had not been converted to rollers yet.

  by BR&P
April 1947 RAILROAD magazine has a Q and A on page 53-54 about new roller bearings. "Officials of the C&O say that a loaded freight car equipped with roller bearings could be started with one-eighth the power required for a similar car equipped with FRICTION BEARINGS" (my capitals) I have also seen references in employee timetables, again speaking of "friction bearings".

My point is, as noted above, that if you're writing an engineering textbook, "plain bearings" might be preferred. But when used in the context of everyday railroad terminology, "friction bearings" is perfectly acceptable because that is what they were called.

Kind of reminds me of a few years back, one of the magazines (TRAINS, maybe?) went to the technically correct wheel arrangements for an articulated steam engine, such as 2-8+8-2. They eventually went back to what most people use, 2-8-8-2 because it had become so commonly used that folks just thought in those terms.

  by txbritt
The railroaders make the terms.

Try telling an engineer that his locomotive is actually equipped with a "horn" instead of a "whistle"