1985 Vol 7, No 3 1

Passenger Car Trucks ... Components and Maintenance - Part 1

By Martin McDonnough

This is the second in a series of highlyinformative articles by veteran Boston Amtrakcar inspector Martin McDonough, a man whogoes all the way back to New Haven heavyweightdays.

His knowledge is extensive and he takes bothpleasure and great pride in sharing with all of us.

All of the photos in this article, unlessotherwise noted, were taken by John Kuehl,Private Varnish Editor.

Pedestals

Pedestals are that portion of the truck framewhich encloses the journal box. As the truckframe moves up and down while the car is inmotion, a great deal of friction develops betweenthe inside pedestal walls and the journal box.Therefore, liners are welded to the pedestal legs.They are of a wraparound type made of highcarbon manganese steel plate. Journal boxes arealso equipped with liners.

Pedestal leg bottoms have a flat base withdrilled and threaded holes. A plate spanning thepedestal jaws is bolted to the bottom of thepedestal legs. This plate is known as a jaw strap,binder strap or tie strap.

The pedestals that enclose the lead wheelsetare of special construction. These inboard legsadjacent to the equalizer coil spring each haveremovable blocks. Each block is inserted into thepedestal leg and is secured by two large flushrivets, although these days some may be welded.These legs are slotted top to bottom and the slotindicates the location of the removable block. Onsix-wheel trucks, the removable blocks (fourinstead of two, one for each equalizer) are all on

the center pedestal. The fully slotted centerpedestal leg is easily seen by referring to thebottom photo on page 3 of the article “PassengerCar Trucks ... An Introduction” (available fromthe AAPRCO Web site). The removable blocksenable the equalizers to be removed as necessary.

Pedestal Inspection and Maintenance

Check all liners and wearing plates. Weldsshould not be cracked or broken. Plates and linersshould be tight. Check to be sure the equalizersare not rubbing against the insides of the pedestallegs. This problem is easily detected by lookingfor shiny wear spots and should be correctedimmediately. Correction is accomplished byeither seating the journal box adapter properly orby shimming the top of the journal box adapter.

Check the distance from the bottom of thejournal box to the top of the jaw strap. It shouldbe at least two inches. Remember the truckmoves up and down while in motion and closerclearances may cause the journal box to strike thejaw strap. This will eventually lead to a roughride or possibly pedestal damage.

The jaw strap should be of single-piececonstruction since the jaw strap aids inmaintaining the correct spacing of your pedestallegs.

On the slotted pedestal legs, hit the jaw strapoccasionally with a hammer. If the jaw straprattles, your bolts are loose. If, on the other hand,your bolts are tight but the jaw strap moves, thenyour flush rivets are coming loose. Time for newrivets. Note: Loose jaw straps rattle and can beheard inside your car. Check after every trip.

Truck Bolster Anchor Rod

On four-wheel trucks (six-wheel too, if soequipped), the truck bolster is usually anchoredto a casting on the truck frame. This device iscalled a bolster anchor and consists of a largesteel rod, four rubber bushings and steel shims.

Martin McDonough is a former Amtrak CarInspector who’s roots go all the way back tothe New Haven Railroad. He resides in HydePark, Massachusetts.

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The bolster anchor keep, the bolster in properalignment at all times.

Inspection and Maintenance

Check for overall tightness, easily done byattempting to pry the anchor up and down with asmall pinch bar.

Check to see if the rod has dropped downand is rubbing the truck frame anchor bracket. Ifthis has happened, a shine will develop on thebottom part of the bracket. This indicates therubber bushings are badly worn and the steelbushings in the bracket are also worn.

The anchor bolster rod should be removedannually. With the rod out you can check thecondition of the rubber bushings and the steelbushings in the mounting brackets. You’ll besurprised to see the wear that can develop whenthe steel bushings wear and the rod begins to ruba hole through the anchor rod mounting brackets.

Swing Hangers

Check your swing hangers occasionally forwear on four-wheel trucks especially where thehanger links are connected to the truck (real easyif you’ve got outside swing hangers). A bit moreeffort is required if you’ve got inside swinghangers. This is an excellent reason to make athorough inspection of those inside swinghangers any time you find your car spotted on aninspection pit. The round swing hanger linkmounting bracket holes are bushed. A goodinspection will show you if these bushings areworn. The swing hanger link pin shouldcompletely fill the hole. If you notice an openspace at the top of the hole, wear is developing.

On six-wheel trucks, a different situationexists. A real good inspection should be madewhen the trucks are rolled out. Some trucks havea recess in the truck frame and you can easily seethe pin and its seat. Others have the pin and itsbushing seat blocked by the bolster. In this case itwill be necessary to remove the bolster in orderto check the pin and seat.

On six-wheel trucks with elliptical springs,check to see these springs are not touching theequalizer. If so, shimming between the swinghanger saddle and the spring plank will eliminatethis problem.

The six-wheel truck bolster (four-wheel too,if applicable) has a recess built in at the bottomto accommodate the elliptical spring. Be sure thespring is properly seated in this recess.

Important maintenance caution: In the eventit becomes necessary to remove a broken coilspring or elliptical spring, make sure themechanics know what they are doing. In order toget sufficient clearance to remove the springs, itwill be necessary to remove the swing hangerbar. The car must be jacked up and then lowereddown on blocking placed under the spring plank.Be extremely careful the blocking is properlypositioned or you will end up with a badly bentspring plank.

Truck Bolster Centerplate Castings

The truck centerplate casting is usuallysecured to the bolster by four steel bolts. Checkto see they are tight.

Check the shims under the centerplatecastings. They should be of a compositionmaterial to dampen truck vibration. Occasionallyyou’ll find wood (oak). Make sure it is notbroken.

Centerplate casting bolts should always beput in from the bottom with the nuts on top. Thisenables you to inspect the centerplate casting fortightness. Nuts should be of the locknut variety

Carbody Centerplate Castings

Use the same procedure as for truck bolstercenterplate castings. Here’s a tip for you. Withthe truck rolled out, take the opportunity toremove all dirt and grease buildups from thecenterplate castings. Then re-lubricate thecastings with lubricants on the market speciallymade for this purpose.

Coil Springs

Inspect coil springs closely. Look for brokensprings. They will usually occur at the bottomcoil. If you have a coil spring with a wide gapbetween coils but find that two coils aretouching, check by reaching your hand aroundthe back of the spring. You will probably findone of the coils is broken.

There should be a distinct gap between thecoils in a spring and you should be able to inserta pencil between the coils. If you can’t, you need

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a new spring or the one you have is an improperspring. The tang (flat end piece) of the springwill have a number stamped on it. Make sure thespring replacement has the same number.

Elliptical Springs

Elliptical springs should have a two-inch ormore gap in the middle between the leaves. If thegap is closer, you need a new spring.

Note: Most cars other than straight coachesare equipped with two or three different types ofequalizer and bolster coil springs. On dining cars,for instance, the lighter dining end will have oneset of springs. On the kitchen there are twodifferent sized springs with the heavier springson the kitchen side to compensate for the muchheavier weight of the range and pantry Ifequalizer springs are changed out, be sure you’regetting the right spring. Check that springnumber.

This final thought on springs — becausethere will never be a perfect roadbed nor aperfect truck your private car will be subjected torocking and rolling. The springs are there todeflect and absorb this motion, preventing mostof it from reaching the carbody.

Truck Equalizers

Check that equalizers are properly seated intheir journal box adapters.

Check the opening in the pedestal leg. If theequalizer is seated properly, it will be evenlyseated midway in the equalizer pedestal legopening. Inspection will show if the equalizer istipped.

Be sure the equalizer is not rubbing againstthe pedestal. Eventually this can lead to a crackin the pedestal leg or a broken equalizer.

Side Bearings

These particular truck components are a veryimportant part of your truck assembly. They areof utmost importance in obtaining a smooth rideand properly maintained, they will preventexcessive rocking.

Constant or Contact Truck Side Bearings

Be sure they are securely bolted.

Periodically remove and check the bearingsprings or rubbers. Replace if worn or damaged.

Be aware of the required adjustment for thistype of bearing. It should be stamped on thebearing housing.

Non-Contact Truck Side Bearings

If the bearing has a roller, be sure it is roundand has no flat spots. Check to see that it will rollfreely in its housing.

Carbody Side Bearing Plate

Directly above your truck-mounted sidebearing is a long, flat rectangular plate. It isbolted to the carbody, with countersunk bolts. Ifthis plate is cracked or broken, change it. If theplate has a groove in it worn by a roller, changeit. Note: A possible serious problem can developinvolving the side bearing plate and a truck sidebearing with a roller. If the side bearing platewere to crack and develop an opening whilegoing through a curve, the roller could catch inthe break. As the truck straightens out, the barholding the side bearing might break or possiblystop the swiveling action of the truck. If thishappens, you could derail.

The A. Stucki Co. of Pittsburgh, PA., hascome out with a resilient side bearing materialthat may be inserted into a non-contact sidebearing housing. The material is large and strongenough to contact the carbody and in effectmakes your side bearing a constant contact type.Definitely worth looking into.

This completes the truck assembly itself. Inthe next issue, we'll complete the truck bycovering roller bearings, with a special sidebaron possible problems that can arise with lateralthrust bearings. Also included will be brakelevers and rods, brakeshoes and a complete trucksummary

For now, I'd like to leave you with thissuggestion. Every private car owner should havea copy of the AAR Field Regulations booklet andcarry it onboard. It is updated every year andcontains all you will need to know about what theAAR expects from you in regards to trucks. Thecost is reasonable and when cost is comparedwith experience gained it becomes almostnegligible.

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Complete inspection of this outside swing hanger truck will be easy.

Complete inspection of an inside swing hanger truck will take more effort. Inside swing hangers on 6-wheeltrucks are easy to see. Watch for that 2 inch minimum opening required at the apex of each elliptical spring.

Comparatively few trucks have not beenmodifiec in some way since originally built.Know how to check these modifications too.

The same truck pictured above has been modifiedwith a modern laterial cushioning device.

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Chipped paint at the truck anchor end indicates that an attempt has been made to move the rod with a pinchbar in order to check the bolster anchor rod for looseness.

While on the inspection pit, make the most of the opportunity and take a good overall look at the entiretruck.

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Next, move on in and check each set of related components, such as the spring plank, spring plank safetystraps, and swing hanger links, bars and springs.

Check each individual item separately.

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This pre-war PRR triple-bolster truck has elliptical and coil springs plus rollers in the truck side bearings.