goutal@parrot.DEC (12/05/84)
Can someone give me (us) a quick tutorial on freight trucks? I see the terms "Bettendorf", "arch-bar", "Timken Roller-Bearing", and am totally lost as to how to recognize them in the field, or what advantages and disadvantages each has, and what period each was used in. I only mentioned a few -- I'm sure there are others. -- Kenn Goutal ...decwrl!dec-rhea!dec-parrot!goutal ? Wed 5-Dec-1984 12:36 EST
chaltas@uiucdcsb.UUCP (12/08/84)
hmm...I don't have any firm dates, but here goes, more or less chronologically. Arch bar trucks are no longer found outside of a few relics. They have not been permitted in interchange for many years -- I think they were banned in the 20's. Their frame is fabricated from steel bars -- roughly in an arch, but with straight lines rather than curves. They were prone to failure and had bolts and such that could come loose. Andrews trucks were designed to ease the financial pain of having to junk the arch bar trucks -- they have a cast frame, much like the Bettendorf design, but use the journal boxes removed from arch bar trucks. Bettendorf trucks are what most people think of as a "normal" truck. (This would be much easier with pictures). Arch bar, Andrews, and Bettendorf trucks are all friction bearing trucks -- the journal boxes were packed with oily whatnot. Roller bearings were used in locomotives in the 30's, but didn't become popular for freight car trucks until the fifties. They have much less friction (rather like ball bearing, but capapble of a much heavier load) and are less prone to overheating (a "hotbox"). Timken is a manufacturere of such bearings as was (is?) Symington. Most trucks now in use have exposed axle ends which you can see turning. The Symington (sp?) design did not. I have recently seen coal hoppers on the ICG that have Bettendory-style trucks that have had their friction bearings replaced with roller bearings. The lid is removed from the journal box and you can see the axle turning inside. There was also an archaic truck design by Fox, which was banned even before the arch bar. It had rigid frames and sprung journals. All the above designs have journals rigidly fixed in sprung frames. I'm told that modern trucks have NO fasteners of any kind in them (nothing to work loose), being held together by gravity. This makes them hard to lift, so spares are often bolted together. George Chaltas uiucdcs!chaltas
gr@uvacs.UUCP (Greg Richardson) (12/10/84)
> Can someone give me (us) a quick tutorial on freight trucks? > I see the terms "Bettendorf", "arch-bar", "Timken Roller-Bearing", > and am totally lost as to how to recognize them in the field, > or what advantages and disadvantages each has, and what period > each was used in. I only mentioned a few -- I'm sure there are others. > -- Kenn Goutal ...decwrl!dec-rhea!dec-parrot!goutal ? > > Wed 5-Dec-1984 12:36 EST The three types of trucks you mention above are by far the main three. In chronological order of use they are 1) Arch-Bar, 2) Bettendorf, and 3) Roller Bearing. Arch bar trucks were popular around and after 1900 - the only ones you will see nowadays are in museums and the like - cars with arch-bar trucks are NOT interchangeable (between railroads that is) by ICC regulations. Also, most arch-bar trucks contained wheels that were cast iron - another ICC inter- change No-No. Arch-bar trucks have the appearance of being made with relatively flat metal bars. There are no smoothly curved sideframe castings; in fact, each piece of the sideframe is bolted together. Bettendorf trucks are made of single piece cast sideframes which has a curved appearence. Like Arch-bar trucks, Bettendorf trucks have friction bearings. This feature can be spotted by the presence of a small spring-loaded door over the axle case. A brass and babbitt pad rests on the top of the axle which is lubricated by an oil-soaked pad which presses against the bottom of the axle. That is the reason for the small door- to check and add oil to the axle case. This truck was popular from the 20s up until 1950. After that time, most cars built had were done so with roller bear- ings. A roller bearing truck has basically the same sideframe as the bettendorf. In fact, many (most) bettendorf trucks have had the friction bearing removed and a roller bearing assembly inserted. This can be spotted by the removal of the axle case door. The main spotting feature for the roller bearing is the rotating end plate on the bearing case. There are several common shapes - triangular, circular, and hexagonal. I cannot think of any others right off. Next time you're out, look for these things - trucks are actually quite easy to distinguish. I hope this makes sense! - Greg Richardson - UVa Academic Computing Center - Charlottesville VA - uvacs!gr
dnc@clyde.UUCP (Don Corey) (12/11/84)
I have a xerox article out of a past issue of "Model Railroader" magazine. It has this to say about freight trucks. Archbar - These trucks have sideframes made of individual metal straps, long bolts, and removable journal boxes. They were first introduced about 1860. In 1938, the ICC banned their use on cars interchanged between railroads because they were subject to metal fatigue. The article states that they are still used on maintenance-of-way cars and other cars not used in interchange service, but I don't know when the article was published. Bettendorf - In 1903, the Bettendorf Co. designed a one piece cast-sideframe truck with integral journal boxes. There were several competitive designs of this truck that differed in shaping, but not in principle. These included Dalman, Symington, and Taylor. Andrews - These trucks look like the bettendorf trucks, but they have a support under the journal box. These trucks could use the journal boxes from the discarded archbar trucks. Roller bearing - The Model Railroader article did not mention roller bearing trucks, and I don't know much about them since I am modeling the early 1950's. To me, the look like Bettendorf trucks with a distinctive disk shaped bearing. I do know that in 1968, the AAR made them mandatory for all new cars. -- Don Corey AT&T Bell Laboratories WH 2A-140 (201) 386-2349 ihnp4!clyde!dnc
wolfram%sri-tsca@tgr.UUCP (12/12/84)
A good place to see all of the truck types is at your friendly local RR hobby shop. I think the Model Die Casting (Roundhouse) old time tank cars have/had Fox trucks. Kadee has nice Andrews. Andrews type, with leaf springs in place of the coils(softer riding), seems to have been popular on older cabooses. Some very old arch bars were flat along the bottom of the sideframe, while newer ones were more like do-it-yourself, or poor man's, skeleton Bettendorfs. Russ
mangoe@umcp-cs.UUCP (Charley Wingate) (12/19/84)
Almost all cabooses these days and all locomotives use what I believe are called "double-hung" trucks. These can be identified by two features: 1. Transversely mounted leaf springs (the end sticks out of the frame) 2. Two short connecting rods or a U-shaped bracket surrounding the springs The way it works is this: the car weight rests upon the springs, as in a normal truck. Instead of resting directly upon the truck frame, however, they rest upon a bar which runs across the truck. The ends of the bar are connected to the bottom ends of the connecting rods, while the tops of the rods are fastened to the frame. If you look carefully, you will notice that the connecting rods point inwards at the top. This allows the sprung weight of the car to sway in and out slightly, reducing transverse shocks. The inward cant of the connectors provides the centering force. I'm sure these trucks have another name, but I can't recall it. I can't ever recall seeing them on anything except a caboose or a locomotive. Charley Wingate umcp-cs!mangoe